0001060955-22-000005 | 20-F | XBRL Viewer

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CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 752,213	$ 840,305
Available for sale investments (Note 3a)	1,712	1,729
Accounts receivable, net (Note 18)	1,342,770	715,271
Unbilled revenue (Note 18)	623,121	428,684
Other receivables	56,760	35,394
Prepayments and other current assets	114,323	53,477
Income taxes receivable (Note 14)	50,299	28,118
Total current assets	2,941,198	2,102,978
Other Assets:
Property, plant and equipment, net (Note 7)	336,444	174,343
Goodwill (Note 4)	9,037,931	936,257
Intangible assets (Note 5)	4,710,843	66,460
Operating right-of-use assets (Note 23)	198,123	84,561
Other non-current assets	70,557	20,773
Non-current income taxes receivable (Note 14)	18,637	17,230
Deferred tax asset (Note 14)	48,392	12,705
Equity method investments (Note 3c)	2,373	4,534
Investments in equity-long term (Note 3b)	22,592	15,765
Total Assets	17,387,090	3,435,606
Current Liabilities:
Accounts payable	90,764	51,113
Unearned revenue (Note 18)	1,323,961	660,883
Other liabilities (Note 8)	949,629	399,769
Income taxes payable (Note 14)	59,433	12,178
Current bank credit lines and loan facilities (Note 24)	55,150	0
Total current liabilities	2,478,937	1,123,943
Other Liabilities:
Non-current bank credit lines and loan facilities (Note 24)	5,381,162	348,477
Non-current operating lease liabilities (Note 23)	159,483	60,801
Non-current other liabilities (Note 9)	41,861	26,366
Non-current government grants	735	838
Non-current income taxes payable (Note 14)	172,109	14,539
Deferred tax liability (Note 14)	1,085,976	10,406
Commitments and contingencies (Note 16)	0	0
Total Liabilities	9,320,263	1,585,370
Shareholders' Equity:
Ordinary shares, par value 6 euro cents per share; 100,000,000 shares authorized, (Note 12), 52,788,093 shares issued and outstanding at December 31, 2020 and 53,622,206 shares issued and outstanding at December 31, 2019.	6,640	4,580
Additional paid-in capital	6,733,910	617,104
Other undenominated capital (Note 13 (a))	1,134	1,134
Accumulated other comprehensive income (Note 22)	(90,937)	(35,477)
Retained earnings	1,416,080	1,262,895
Total Shareholders’ Equity	8,066,827	1,850,236
Total Liabilities and Shareholders’ Equity	$ 17,387,090	$ 3,435,606

CONSOLIDATED BALANCE SHEETS (Parenthetical) - € / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Ordinary shares, par value (in EUR per share)	€ 6	€ 6
Ordinary shares, shares authorized (in shares)	100,000,000	100,000,000
Ordinary shares, shares issued (in shares)	81,554,683	52,788,093
Ordinary shares, shares outstanding (in shares)	81,554,683	52,788,093

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue:
Revenue	$ 5,480,826	$ 2,797,288	$ 2,805,839
Costs and expenses:
Direct costs (excluding depreciation and amortization)	3,972,612	1,979,883	1,974,135
Selling, general and administrative	585,330	342,449	332,663
Depreciation and amortization	314,987	66,126	61,550
Transaction and integration related (Note 6)	198,263	(759)	4,085
Restructuring (Note 15)	31,105	18,089	0
Total costs and expenses	5,102,297	2,405,788	2,372,433
Income from operations	378,529	391,500	433,406
Interest income	574	2,724	6,859
Interest expense (Note 24)	(182,423)	(13,019)	(13,276)
Income before income tax expense	196,680	381,205	426,989
Income tax expense (Note 14)	(41,334)	(47,875)	(51,133)
Income before share of earnings from equity method investments	155,346	333,330	375,856
Share of equity method investments	(2,161)	(366)	0
Net Income	153,185	332,964	375,856
Net income attributable to noncontrolling interest	0	(633)	(1,870)
Net income attributable to the Group	$ 153,185	$ 332,331	$ 373,986
Net income per Ordinary Share attributable to the Group (Note 27):
Basic (USD per share)	$ 2.28	$ 6.20	$ 6.85
Diluted (USD per share)	$ 2.25	$ 6.15	$ 6.79
Weighted average number of ordinary shares outstanding:
Basic (in shares)	67,110,186	52,859,911	53,859,537
Diluted (in shares)	68,068,311	53,283,585	54,333,461

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 153,185	$ 332,964	$ 375,856
Other comprehensive income, net of tax
Currency translation adjustment	(60,092)	48,129	(1,313)
Currency impact of long-term funding	(525)	(1,603)	(2,710)
Unrealized capital (loss)/gain - investments	0	(231)	681
Actuarial gain/(loss) on defined benefit pension plan	4,266	(4,138)	(2,226)
Amortization of interest rate hedge	113	(910)	(923)
Settlement of interest rate hedge	778	(905)	0
Total comprehensive income	97,725	373,306	369,365
Less net income attributable to noncontrolling interest	0	(633)	(1,870)
Total comprehensive income attributable to the Group	$ 97,725	$ 372,673	$ 367,495

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	Total	Ordinary Shares	Additional Paid-in Capital	Other Undenominated Capital	Accumulated Other Comprehensive Income	Retained Earnings	Redeemable Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2018		53,971,706
Beginning balance at Dec. 31, 2018	$ 1,354,281	$ 4,658	$ 529,642	$ 983	$ (69,328)	$ 888,326
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	373,986					373,986
Currency translation adjustment	(1,313)				(1,313)
Currency impact of long-term funding	(2,710)				2,710
Unrealized capital (loss)/gain - investments	681				681
Actuarial gain (loss) on defined benefit pension plan	(2,226)				(2,226)
Amortization of interest rate hedge	(923)				(923)
Loss on interest rate hedge	0
Total comprehensive income attributable to the Group	367,495
Exercise of share options (in shares)		329,870
Exercise of share options	21,621	$ 22	21,599
Issue of restricted share units / performance share units (in shares)		355,730
Issue of restricted share units / performance share units	24	$ 24
Share based compensation expense	26,733		26,733
Share issue costs	(13)		(13)
Repurchase of ordinary shares (in shares)		(1,035,100)
Repurchase of ordinary shares	(146,931)	$ (69)		69		(146,931)
Share repurchase costs	(107)					(107)
Exercise of call option on noncontrolling interest shares	(5,048)					(5,048)
Ending balance (in shares) at Dec. 31, 2019		53,622,206
Ending balance at Dec. 31, 2019	1,618,055	$ 4,635	577,961	1,052	(75,819)	1,110,226
Beginning balance at Dec. 31, 2018							$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income							1,870
Noncontrolling interest adjustment to redemption amount							32,592
Exercise of call option on noncontrolling interest shares							5,048
Ending balance at Dec. 31, 2019							39,510
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	332,331					332,331
Currency translation adjustment	48,129				48,129
Currency impact of long-term funding	(1,603)				(1,603)
Unrealized capital (loss)/gain - investments	(231)				(231)
Actuarial gain (loss) on defined benefit pension plan	(4,138)				(4,138)
Amortization of interest rate hedge	(910)				(910)
Loss on interest rate hedge	(905)				(905)
Total comprehensive income attributable to the Group	372,673
Exercise of share options (in shares)		193,417
Exercise of share options	13,189	$ 13	13,176
Issue of restricted share units / performance share units (in shares)		207,688
Issue of restricted share units / performance share units	14	$ 14
Share based compensation expense	25,981		25,981
Share issue costs	(14)		(14)
Repurchase of ordinary shares (in shares)		(1,235,218)
Repurchase of ordinary shares	(175,000)	$ (82)		82		(175,000)
Share repurchase costs	$ (140)					(140)
Ending balance (in shares) at Dec. 31, 2020	52,788,093	52,788,093
Ending balance at Dec. 31, 2020	$ 1,850,236	$ 4,580	617,104	1,134	(35,477)	1,262,895
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income							633
Noncontrolling interest adjustment to redemption amount	(4,522)					(4,522)	4,522
Exercise of call option on noncontrolling interest shares							(44,665)
Ending balance at Dec. 31, 2020							$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	153,185					153,185
Currency translation adjustment	(60,092)				(60,092)
Currency impact of long-term funding	(525)				(525)
Unrealized capital (loss)/gain - investments	0
Actuarial gain (loss) on defined benefit pension plan	4,266				4,266
Amortization of interest rate hedge	113				113
Loss on interest rate hedge	778				778
Total comprehensive income attributable to the Group	97,725
Exercise of share options (in shares)		1,065,529
Exercise of share options	118,589	$ 77	118,512
Issue of restricted share units / performance share units (in shares)		328,634
Issue of restricted share units / performance share units	23	$ 23
Share based compensation expense	133,553		133,553
Share issue costs	(853)		(853)
Issue of shares associated with a business combination (in shares)		27,372,427
Issue of shares associated with a business combination	5,658,155	$ 1,960	5,656,195
Replacement share-based awards issued to acquiree employees	$ 209,399		209,399
Ending balance (in shares) at Dec. 31, 2021	81,554,683	81,554,683
Ending balance at Dec. 31, 2021	$ 8,066,827	$ 6,640	$ 6,733,910	$ 1,134	$ (90,937)	$ 1,416,080

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended			36 Months Ended	48 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 153,185	$ 332,964	$ 375,856
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	314,987	66,126	61,550
Fixed asset impairment	20,037	5,411	0
Reduction in carrying value of operating right-of-use assets	45,339	28,480	30,372
Loss on equity method investments	2,161	366	0
Charge/(credit) on interest rate hedge	891	(910)	(923)
Amortization of financing costs and debt discount	12,890	523	540
Stock compensation expense	133,844	26,271	26,819
Loss on extinguishment of debt	73,894	0	0
Deferred tax (benefit)/expense	(60,616)	927	(1,537)
Unrealized foreign exchange (gain)/loss	(6,054)	5,979	590
Other non-cash items	3,589	(6,949)	2,018
Changes in operating assets and liabilities, net of acquired assets and assumed liabilities:
Accounts receivable	113,513	(175,040)	(101,545)
Unbilled revenue	(17,656)	(5,748)	(55,790)
Unearned revenue	(69,121)	291,844	86,567
Other net assets	108,259	(2,209)	(11,976)
Net cash provided by operating activities	829,142	568,035	412,541
Cash flows from investing activities:
Purchase of property, plant and equipment	(93,750)	(40,885)	(38,948)
Purchase of subsidiary undertakings (net of cash acquired)	(5,914,475)	(47,931)	(131,272)
Investment in equity method investments	(2,450)	(2,450)	0
Loan to equity method investment	(10,000)	0	0
Sale of available for sale investments	497	47,902	21,686
Purchase of available for sale investments	(480)	0	(9,603)
Purchase of investments in equity - long term	(3,577)	(3,212)	(3,890)	$ (13,300)	$ (16,900)
Net cash used in investing activities	(6,024,235)	(46,576)	(162,027)
Cash flows from financing activities:
Financing costs	(30,328)	(1,554)	0
Drawdown of credit lines and facilities	5,905,100	350,000	0
Repayment of credit lines and facilities	(877,780)	(350,000)	0
Purchase of noncontrolling interest	0	(43,923)	0
Proceeds from the exercise of equity compensation	118,589	13,203	21,645
Share issue costs	(853)	(14)	(13)
Repurchase of ordinary shares	0	(175,000)	(146,931)
Share repurchase costs	0	(140)	(107)
Settlement of interest rate hedge	0	(905)	0
Net cash provided by financing activities	5,114,728	(208,333)	(125,406)
Effect of exchange rate movements on cash	(7,727)	6,870	(650)
Net (decrease)/increase in cash and cash equivalents	(88,092)	319,996	124,458
Cash and cash equivalents at beginning of year	840,305	520,309	395,851
Cash and cash equivalents at end of year	$ 752,213	$ 840,305	$ 520,309	$ 840,305	$ 752,213

Description of business	12 Months Ended
Description of business	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of business	Description of business ICON plc and its subsidiaries ("the Company" or "ICON") is a clinical research organization ("CRO"), providing outsourced development services on a global basis to the pharmaceutical, biotechnology and medical device industries. We specialize in the strategic development, management and analysis of programs that support all stages of the clinical development process from compound selection to Phase I-IV clinical studies. Our mission is to improve the lives of patients by accelerating the development of our customers' drugs and devices through innovative solutions. We believe that we are one of a select group of CROs with the expertise and capability to conduct clinical trials in most major therapeutic areas on a global basis and have the operational flexibility to provide development services on a stand-alone basis or as part of an integrated "full-service" solution. At December 31, 2021 we had approximately 38,330 employees, in 142 locations in 53 countries. During the year ended December 31, 2021, we derived approximately 47.1%, 46.4% and 6.5% of our revenue in the United States, Europe and Rest of World, respectively. ICON’s ordinary shares are traded on the NASDAQ Global Select Market under the symbol “ICLR”. We began operations in 1990 and have expanded our business through internal growth, together with a number of strategic acquisitions to enhance our capabilities and expertise in certain areas of the clinical development process. We are incorporated in Ireland and our principal executive office is located at: South County Business Park, Leopardstown, Dublin 18, Republic of Ireland. The contact telephone number of this office is +353 1 2912000.

Significant accounting policies

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Significant accounting policies

The accounting policies noted below were applied in the preparation of the accompanying financial statements of the Company and are in conformity with accounting principles generally accepted in the United States.

(a) Basis of consolidation

The consolidated financial statements include the financial statements of the Company and all of its subsidiaries. All significant intercompany profits, transactions and account balances have been eliminated. The results of subsidiary undertakings acquired in the period are included in the Consolidated Statement of Operations from the date of acquisition.

(b) Use of estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates. The principal management estimates and judgments used in preparing the financial statements relate to revenue recognition and intangible assets acquired in a business combination.

The Company earns revenues by providing a number of different services to its customers. These services, which are integral elements of the clinical development process, include clinical trials management, consulting, contract staffing, data services and laboratory services. Contracts range in duration from a number of months to several years.

ASC 606 requires application of five steps: (1) identify the contract(s) with a customer; (2) identify the performance obligation in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies the performance obligation(s), which have been applied to revenue recognized from each service described below.

Clinical trial service revenue

A clinical trial service is a single performance obligation satisfied over time, i.e. the full-service obligation in respect of a clinical trial (including those services performed by investigators and other parties) is considered a single performance obligation. Promises offered to the customer are not distinct within the context of the contract. ICON is the contract principal in respect of both direct services and in the use of third parties (principally investigator services) that support the clinical research projects. The transaction price is determined by reference to the contract or change order value (total service revenue and pass-through/ reimbursable expenses) adjusted to reflect a realizable contract value. Revenue is recognized over time as the single performance obligation is satisfied. The progress towards completion for clinical service contracts is measured based on an input measure being total project costs incurred (inclusive of pass-through/ reimbursable expenses) at each reporting period as a percentage of forecasted total project costs.

Laboratory services revenue

Revenue is recognized when, or as, obligations under the terms of a contract are satisfied, which occurs when control of the products or services are transferred to the customer. Revenue for laboratory services is measured as the amount of consideration we expect to receive in exchange for transferring products or services. Where contracts with customers contain multiple performance obligations, the transaction price is allocated to each performance obligation based on the estimated relative selling price of the promised good or service. Service revenue is recognized over time as the services are delivered to the customer based on the extent of progress towards completion of the performance obligation. The determination of the methodology to measure progress requires judgment and is based on the nature of services provided. This requires an assessment of the transfer of value to the customer. The right to invoice measure of progress is generally related to rate per unit contracts, as the extent of progress towards completion is measured based on discrete service or time-based increments, such as samples tested or labor hours incurred. Revenue is recorded in the amount invoiced since that amount corresponds to the value of the Company's performance and the transfer of value to the customer.

Contracting services revenue

The Company has availed of the practical expedient which results in recognition of revenue on a right to invoice basis. Application of the practical expedient reflects the right to consideration from the customer in an amount that corresponds directly with the value to the customer of the performance completion to date. This reflects hours performed by contract staff.

Consulting services revenue

Our consulting services contracts represent a single performance obligation satisfied over time. The transaction price is determined by reference to contract or change order value. Revenue is recognized over time as the performance obligation is satisfied. The progress towards completion for consulting contracts is measured based on total project inputs (time) at each reporting period as a percentage of forecasted total project inputs.

Data services revenue

The Company provides data reports and analytics to customers based on agreed-upon specifications, including the timing of delivery, which is typically either weekly, monthly, or quarterly. If a customer requests more than one type of data report or series of data reports within a contract, each distinct type of data report is a separate performance obligation. The contracts provide for the Company to be compensated for the value of each deliverable. The transaction price is determined using list prices, discount agreements, if any, and negotiations with the customers, and generally includes any out-of-pocket expenses. Typically, the Company bills in advance of services being provided with the amount being recorded as unearned revenue.

When multiple performance obligations exist, the transaction price is allocated to performance obligations on a relative standalone selling price basis. In cases where the Company contracts to provide a series of data reports, or in some cases data, the Company recognizes revenue over time using the “units delivered” output method as the data or reports are delivered. Expense reimbursements are recorded to revenue as the expenses are incurred as they relate directly to the services performed.

Certain arrangements include upfront customization or consultative services for customers. These arrangements often include payments based on the achievement of certain contractual milestones. Under these arrangements, the Company contracts with a customer to carry out a specific study, ultimately resulting in delivery of a custom report or data product. These arrangements are a single performance obligation given the integrated nature of the service being provided. The Company typically recognizes revenue under these contracts over time, using an output-based measure, generally time elapsed, to measure progress and transfer of control of the performance obligation to the customer. Expense reimbursements are recorded to revenue as the expenses are incurred as they relate directly to the service performed.

The Company enters into contracts with some of its larger data suppliers that involve non-monetary terms. The Company issues purchase credits to be used toward the data supplier's purchase of the Company's services based on the fair value of the data obtained. In exchange, the Company receives monetary discounts on the data received from the data suppliers. The fair value of the revenue earned from the customer purchases is recognized as services are delivered as described above. At the end of the contract year, any unused customer purchase credits may be forfeited or carried over to the next contract year based on the terms of the data supplier contract.

Commissions

Incremental costs of obtaining a contract are recognized as an asset on the Consolidated Balance Sheet in respect of those contracts that exceed one year. Where commission costs relate to contracts that are less than one year, the practical expedient is applied as the amortization period of the asset which would arise on deferral would be one year or less.

(d) Pass-through/ Reimbursable expenses

Pass through/ Reimbursable expenses comprise investigator payments and certain other costs which are reimbursed by clients under terms specific to each contract to the investigators. See note 2 (e) Direct costs below.

(e) Direct costs

Direct costs consist of compensation, associated employee benefits and share-based payments for project-related employees and other direct project-related costs.

Reimbursable expenses are presented within direct costs. This presentation is to align the presentation of costs with our assessment that our clinical trial service is a single performance obligation satisfied over time i.e. the full-service obligation is in respect of a clinical trial (including those services performed by investigators and other parties) is considered a single performance obligation. Reimbursable expenses are recorded once the activity which forms the basis for the cost has occurred.

Investigator payment costs are recorded and reported reflecting investigator activity over the life of the contract. Investigator payments are made based on predetermined contractual arrangements. Timing of payments may differ from the recording and reporting of the expense which is based on activity.

(f) Advertising costs

All costs associated with advertising and promotion are expensed as incurred.

(g) Foreign currencies and translation of subsidiaries

ICON plc's financial statements are prepared in United States dollars. Transactions in currencies other than the functional currency of the individual entities within the ICON Group are recorded at the rate ruling at the date of the transaction. Monetary assets and liabilities denominated in currencies other than the functional currency of the individual entities within the ICON Group are translated into the functional currency of that entity at exchange rates prevailing at the Balance Sheet date. Adjustments resulting from these translations are charged or credited to income. Amounts charged or credited to the Consolidated Statements of Operations for the years ended December 31, 2021, December 31, 2020 and December 31, 2019 were as follows:


	Year ended December 31,
	2021		2020		2019
	(in thousands)
Amounts (credited)/charged	$	(14,316)	$	5,979	$	590

The financial statements of subsidiaries with other functional currencies are translated at period end rates for the Consolidated Balance Sheets and average rates for the Consolidated Statements of Operations. Translation gains and losses arising are reported as a movement on accumulated other comprehensive income. Foreign currency transaction gains and losses are reported in other comprehensive income ("currency impact of long term funding") rather than through income where the foreign currency transaction is 'long-term investment' in nature i.e. settlement is not planned or anticipated in the foreseeable future.

(h) Disclosure of fair value of financial instruments

Cash, cash equivalents, other receivables, available for sale investments, accounts receivable, accounts payable, investigator payments and income taxes payable have carrying amounts that approximate fair value due to the short term maturities of these instruments. Other liabilities' carrying amounts approximate fair value based on net present value of estimated future cash flows. Debt is measured at historical cost.

Financial instruments are measured in the Consolidated Balance Sheet at amortized cost or fair value using a fair value hierarchy of valuation inputs. The fair value hierarchy prioritizes the inputs into three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of three levels, which is determined by the lowest level input that is significant to the fair value measurement in its entirety. These levels are:


Level 1:			Inputs are based upon unadjusted quoted prices for identical instruments traded in active markets.

Level 2:			Inputs are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3:			Inputs are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability.

The Company classifies its investments in short term debt or equity investments as available for sale, as it does not actively trade such securities nor does it intend to hold them to maturity. The fair value of short term investments are represented by level 1 fair value measurements – quoted prices in active markets for identical assets. The unrealized movements in fair value are recognized in equity until disposal or sale, at which time, those unrealized movements from prior periods are recognized in the Consolidated Statement of Operations. Losses other than temporary, which reduce the carrying amount below cost are recognized in Consolidated Statement of Operations.

(i) Business combinations

The cost of a business combination is measured as the aggregate of the fair values at the date of exchange of assets given, liabilities incurred or assumed and equity instruments issued in exchange for control. Where a business combination agreement provides for an adjustment to the cost of the acquisition which is contingent upon future events, the amount of the estimated adjustment is recognized at the acquisition date at the fair value of the contingent consideration. Any changes to this estimate outside the measurement period will depend on the classification of the contingent consideration. If the contingent consideration is classified as equity it shall not be re-measured and the settlement shall be accounted for within equity. If the contingent consideration is classified as a liability any adjustments will be accounted for through the Consolidated Statement of Operations or Other Comprehensive Income depending on whether the liability is considered a financial instrument.

The assets, liabilities and contingent liabilities of businesses acquired are measured at their fair values at the date of acquisition. In the case of a business combination which is completed in stages, the fair values of the identifiable assets, liabilities and contingent liabilities are determined at the date of each exchange transaction. When the initial accounting for a business combination is determined provisionally, any subsequent adjustments to the provisional values allocated to the identifiable assets, liabilities and contingent liabilities are made within twelve months of the acquisition date and presented as adjustments to goodwill in the reporting period in which the adjustments are determined.

The Company allocates a share of net income to the noncontrolling interest holders based on percentage ownership.

(j) Goodwill and Impairment

Goodwill represents the excess of the cost of acquired entities over the net amounts assigned to assets acquired and liabilities assumed. Goodwill primarily comprises acquired workforce in place which does not qualify for recognition as an asset apart from goodwill. Goodwill is stated net of any provision for impairment. The Company tests goodwill annually for any impairments or whenever events occur which may indicate impairment. An impairment charge would be recognized for any amount by which the carrying amount exceeds the reporting unit's fair value up to the amount of existing goodwill. The Company performs a qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. No impairment was recognized as a result of the impairment testing carried out for the years ended December 31, 2021, December 31, 2020 and December 31, 2019.

(k) Intangible assets

Intangible assets are amortized on a straight line basis over their estimated useful life.

(l) Cash and cash equivalents

Cash and cash equivalents include cash and highly liquid investments with initial maturities of three months or less and are stated at cost, which approximates market value.

(m) Investments in debt, equity and other

Available for sale investments

The Company classifies short-term investments as available for sale in accordance with the terms of ASC 320 'Investments - Debt and Equity Securities'. Realized gains and losses are determined using specific identification. The investments are reported at fair value, with unrealized gains or losses reported in a separate component of shareholders' equity. Any differences between the cost and fair value of the investments are represented by accrued interest and unrealized gains/losses.

Long term investments

The Company classifies its interests in funds having considered the nature of its investment, the extent of influence over operating and financial decisions and the availability of readily determinable fair values. The Company determined that the interests in funds at December 31, 2021 meet the definition of equity securities without readily determinable fair values. The Company concluded that the interests held at December 31, 2020 and December 31, 2021 qualify for the NAV practical expedient in ASC 820 'Fair value measurements and disclosures'. Any increases or decreases in fair value are recognized in net income in the period. These are therefore measured at Level 3 of the fair value hierarchy.

Equity method investments

The Company’s investments that are not consolidated are accounted for under the equity method if the Company exercises significant influence that is considered to be greater than minor. These investments are classified as equity method investments on the accompanying Consolidated Balance Sheet. The Company records its pro rata share of the earnings/losses of these investments in Share of equity method investments in the Consolidated Statement of Operations. The Company reviews these for impairment whenever events or changes in circumstances indicate that the carrying amounts may not be recoverable.

(n) Accounts receivable, net and unbilled revenue

Accounts receivable and unbilled revenue are recorded at fair value less an estimate of the credit losses expected to be incurred on the Company's accounts receivable portfolio. The Company's estimate of expected credit losses considers historical credit loss information that is adjusted, where necessary, for current conditions and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. The Company's receivables and unbilled services are predominantly due from large and mid-tier pharmaceutical and biotechnology companies that share similar risk characteristics. The Company monitors their portfolio of receivables and unbilled services for any deterioration in current or expected credit quality (for example, expected delinquency level), and adjusts the allowance for credit losses as required.

Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense in the Consolidated Statement of Operations. Losses are charged against the allowance when management believes the uncollectibility of a previously provisioned amount is confirmed.

Accounts receivable factoring

Where the Company enters into an agreement to sell certain portfolios of its accounts receivable balances, the sale is accounted for in accordance with ASC Topic 860 'Transfers and Servicing' (ASC 860). Agreements which result in true sales of the transferred receivables, as defined in ASC 860, which occur when receivables are transferred without recourse to ICON, are excluded from amounts reported in the Consolidated Balance Sheet. Cash proceeds received from such sales are included in operating cash flows. The associated finance costs are presented as interest expense.

(o) Inventory

Inventory is valued at the lower of cost and net realizable value and after provisions for obsolescence. The cost of inventories comprises the purchase price and attributable costs, less trade discounts. At December 31, 2021 the carrying value of inventory, included within prepayments and other current assets on the Consolidated Balance Sheet, was $5.8 million (2020: $4.8 million).

(p) Property, plant and equipment

Property, plant and equipment is stated at cost less accumulated depreciation. Depreciation of property, plant and equipment is computed using the straight line method based on the estimated useful lives of the assets as listed below:


			Years
Building			40
Computer equipment and software			2-8
Office furniture and fixtures			8
Laboratory equipment			5
Motor vehicles			5

Leasehold improvements are amortized using the straight line method over the estimated useful life of the asset or the lease term, whichever is shorter.

(q) Leases

The Company adopted ASC 842 'Leases' (ASC 842), with a date of initial application of January 1, 2019. The lease accounting policy applied in preparation of the results for the year ended December 31, 2020 and December 31, 2021 therefore reflect application of ASC 842. The Company adopted the standard using the cumulative-effect adjustment approach. Under this transition method, the Company applied the ASC 842 as at the date of initial application (i.e. January 1, 2019), without restatement of comparative period amounts. The cumulative effect of applying the standard is recorded as an adjustment to the opening consolidated balance sheet as at the date of initial application.

ASC 842 requires lessees to recognize the rights and obligations resulting from virtually all leases on the Consolidated Balance Sheet as right-of-use (ROU) assets with corresponding lease liabilities.

The most significant impact of application of the standard for the Company related to the recognition of right-of-use assets and lease liabilities on the Consolidated Balance Sheet for operating leases for certain property, vehicles and equipment. Prior to application of ASC 842, costs in respect of operating leases were charged to the Consolidated Statements of Operations on a straight-line basis over the lease term.

Pursuant to certain practical expedients available as part of adopting ASC 842, ICON did not reassess whether existing or expired supplier contracts are or contain leases, the classification of existing or expired leases, or whether unamortized initial direct costs meet the new definition of initial direct costs under ASC 842. Additionally, the Company elected to use hindsight in determining the lease term and in assessing impairment of ROU assets, if any.

The Company determines if an arrangement is a lease at inception. Finance leases, if any, are depreciated on the same basis as property, plant and equipment. At December 31, 2021 and December 31, 2020, the Company did not account for any leases as finance leases.

Operating leases are included in operating right-of-use assets, other liabilities and non-current operating lease liabilities on our Consolidated Balance Sheet with the lease charge recognized on a straight-line basis over the lease term. ROU assets and lease liabilities are recognized based on the present value of future minimum lease payments over the lease term at commencement date or date of transition. Our lease terms may also include options to extend or terminate. The Company actively reviews options to extend or terminate leases and adjusts the ROU asset and lease liability when it is reasonably certain the option will be exercised. The ROU asset is adjusted for any prepayments made at the date of commencement and any initial direct costs incurred. As most of the Company's leases do not provide an implicit rate, the discount rate used is based on the rate of traded corporate bonds available at the commencement date adjusted for country risk, liquidity and lease term.

The Company accounts for lease and non-lease components separately with lease components flowing through the Consolidated Balance Sheet and non-lease components expensed directly to the Consolidated Statements of Operations.

Leasehold improvements are amortized over the shorter of the depreciable lives of the corresponding fixed assets or the lease term including any applicable renewals. Certain property leases include variable lease payments resulting from periodic rent increases based on an index which cannot be reasonably estimated at the lease commencement date. These costs are expensed as incurred on the Consolidated Statements of Operations.

In some cases, the Company enters into sublease agreements and becomes both a lessee and a lessor for the same underlying asset. Although subleases are accounted for separately from the lease they relate to, subleases are accounted for in the same way as other leases.

(r) Income taxes

The Company applies the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amount of existing assets and liabilities and their respective tax bases and for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which these temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are reduced by a valuation allowance to the amount that is more likely than not to be realized. The Company recognizes the effect of income tax positions only if those positions will more likely than not be sustained. Recognized income tax positions are measured at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon settlement. Interest and penalties related to income taxes are included in income tax expense and classified with the related liability on the Consolidated Balance Sheet. The Company accounts for the impact of GILTI (“global intangible low-taxed income”) in the period it arises and has therefore not provided for deferred taxes in respect of this item.

(s) Government grants

Government grants received relating to capital expenditures are shown by deducting the grant from the asset's carrying amount and crediting them to income on a basis consistent with the depreciation policy of the relevant assets. Grants relating to categories of operating expenditures are shown as deferred income and credited to income in the period in which the expenditure to which they relate is charged.

Under the grant agreements amounts received may become repayable in full should certain circumstances specified within the grant agreements occur, including downsizing by the Company, disposing of the related assets, ceasing to carry on its business or the appointment of a receiver over any of its assets. The Company has not recognized any loss contingency having assessed as remote the likelihood of these events arising.

(t) Research and development credits

Research and development credits are available to the Company under the tax laws in certain jurisdictions, based on qualifying research and development spend as defined under those tax laws. Research and development credits are generally recognized as a reduction of income tax expense. However, certain tax jurisdictions provide refundable credits that are not wholly dependent on the Company's ongoing income tax status or income tax position. In these circumstances the benefit of these credits is not recorded as a reduction to income tax expense, but rather as a reduction of operating expenditure.

(u) Pension costs

The Company contributes to defined contribution plans covering all eligible employees. The Company contributes to these plans based upon various fixed percentages of employee compensation and such contributions are expensed as incurred.

The Company operates, through certain subsidiaries, a defined benefit plan for certain employees located in the United Kingdom and Switzerland. The Company accounts for the costs of these plans in accordance with ASC 715-30 'Defined Benefit Plans – Pension'. These plans are presented in accordance with the requirements of ASC 715-60 'Defined Benefit Plans – Other Postretirement'. The Company also maintains various retirement plans across the Group, many of which are required by local employment laws.

(v) Redeemable noncontrolling interests and equity

The Company acquired a majority ownership interest in MeDiNova during the year ended December 31, 2019. Included in the purchase agreement were put and call option arrangements with the noncontrolling interest holders that required (put option) or enabled (call option) the Company to purchase the remaining minority ownership at a future date. The option was accounted for as temporary equity, which is presented separately as redeemable noncontrolling interest on the Consolidated Balance Sheet. This classification reflects the assessment that the instruments are contingently redeemable in accordance with ASC 480-10-S99 'Distinguishing Liabilities from Equity'. On March 9, 2020, ICON exercised its option to call the remaining shares and took 100% ownership of MeDiNova.

Redeemable noncontrolling interests are accreted to their redemption value over the period from the date of issuance to the first date on which the option is exercisable. The change in the option's redemption value is recorded against retained earnings. In a computation of earnings per share, the accretion of redeemable noncontrolling interests to their redemption value is a reduction of net income attributable to the Group. Basic and diluted net income per ordinary share attributable to the Group includes the adjustment to reflect the accretion of the noncontrolling interest to its redemption value until the redemption of the noncontrolling interest on March 9, 2020.

(w) Net income per ordinary share

Basic net income per ordinary share attributable to the Company has been computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding during the period. Diluted net income per ordinary share is computed by adjusting the weighted average number of ordinary shares outstanding during the period for all potentially dilutive ordinary shares outstanding during the period and adjusting net income for any changes in income or loss that would result from the conversion of such potential ordinary shares. There is no difference in net income used for basic and diluted net income per ordinary share. Basic and diluted net income per ordinary share attributable to the Company includes the adjustment to reflect the accretion of the noncontrolling interest in MeDiNova to its redemption value (see note 27 - Net income per ordinary share).

(x) Share-based compensation

The Company accounts for its share options, Restricted Share Units ("RSUs") and Performance Share Units ("PSUs") in accordance with the provisions of ASC 718 'Compensation – Stock Compensation'. Share-based compensation expense for equity-settled awards made to employees and directors is measured and recognized based on estimated grant date fair values. These equity-settled awards include employee share options, RSUs and PSUs.

Share-based compensation expense for share options awarded to employees and directors is estimated at the grant date based on each option's fair value as calculated using the Black-Scholes option-pricing model. Share-based compensation for RSUs and PSUs awarded to employees and directors is calculated based on the market value of the Company's shares on the date of award of the RSUs and PSUs. The value of awards expected to vest is recognized as an expense over the requisite service periods. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs materially from original estimates.

Estimating the grant date fair value of share options as of the grant date using an option-pricing model, such as the Black-Scholes model, is affected by the Company's share price as well as assumptions regarding a number of complex variables. These variables include, but are not limited to, the expected share price volatility over the term of the awards, risk-free interest rates and the expected term of the awards.

Liability classified awards are measured at the fair value of the award on the grant date and remeasured at each reporting period at fair value until the award is settled.

Replacement awards

In connection with the completion of the Merger, the company issued replacement awards to the holders of PRA equity awards on July 1, 2021. An exchange of share-based compensation awards in a business combination is treated as a modification under ASC 718. The replacement awards and the original acquiree awards are measured at fair value at the acquisition date and calculated using the fair-value-based measurement principles in ASC 718. Amounts attributable to pre-combination vesting are accounted for as part of the consideration transferred for the acquiree. Amounts attributable to post-combination vesting are accounted for separate from the business combination and are recognized as compensation cost in the post-combination period.

(y) Impairment of long-lived assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of the asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured at the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets to be disposed of are reported at the lower of the carrying amount of the asset or fair value less selling costs.

(z) Derivative financial instruments

We enter into transactions in the normal course of business using various financial instruments in order to hedge against exposure to fluctuating exchange and interest rates. We use derivative financial instruments to reduce exposure to fluctuations in interest rates. A derivative is a financial instrument or other contract whose value changes in response to some underlying variable, which has an initial net investment smaller than would be required for other instruments that have a similar response to the variable and that will be settled at a future date. We do not enter into derivative financial instruments for trading or speculative purposes. We did not hold any interest rate swap contracts or forward currency contracts at December 31, 2021 or December 31, 2020.

We use derivative financial instruments to reduce exposure to fluctuations in foreign exchange rates. During the years ended December 31, 2019 and December 31, 2020, we entered into forward currency contracts in respect of identified exposure arising from euro payments. All contracts expired during the year in which the contract was entered into. No forward currency contracts were entered into during the year ended December 31, 2021.

Our accounting policies for derivative financial instruments are based on whether they meet the criteria for designation as cash flow or fair value hedges. A designated hedge of the exposure to variability in the future cash flows of an asset or a liability, or of a forecast transaction, is referred to as a cash flow hedge. A designated hedge of the exposure to changes in fair value of an asset or a liability is referred to as a fair value hedge. The criterion for designating a derivative as a hedge includes the assessment of the instrument's effectiveness in risk reduction, matching of the derivative instrument to its underlying transaction and the probability that the underlying transaction will occur. For derivatives with cash flow hedge accounting designation, we report the gain or loss from the effective portion of the hedge as a component of Other Comprehensive Income and reclassify it into earnings in the same period or periods in which the hedged transaction affects earnings and within the same Consolidated Statement of Operations line item as the impact of the hedged transaction. For derivatives with fair value hedge accounting designation, we recognize gains or losses from the change in fair value of these derivatives, as well as the offsetting change in the fair value of the underlying hedged item, in earnings. Fair value gains and losses arising on derivative financial instruments not qualifying for hedge accounting are reported in our Consolidated Statement of Operations.

The company has entered into certain put and call arrangements to purchase equity in unconsolidated entities at a future date. These arrangements are accounted for at fair value at the balance sheet date.

(aa) Debt issuance costs

Debt issuance costs relating to the Company’s long-term debt are recorded as a direct reduction of long-term debt; these costs are deferred and amortized to interest expense using the effective interest method, over the respective terms of the related debt. Debt issuance costs relating to the Company’s revolving credit facilities are recorded as an asset; these costs are deferred and amortized to interest expense using the straight-line method. Early repayment of debt facilities can result in modification of the debt and the acceleration of the amortization of debt issuance costs.

(ab) Transaction and integration-related expenses

Transaction and integration-related expenses are the incremental costs directly attributable to the completion and integration activities associated with the Company’s recent acquisitions. The costs consist of investment banking fees, advisory costs, retention agreements with employees, accelerated share compensation charges, contingent consideration valuation adjustments and ongoing integration activities. The Company accounts for these transaction and integration-related costs as expenses in the period in which the costs are incurred and the services are received.

(ac) Restructuring

Restructuring charges reflect certain one-time costs arising from reorganization programs announced by Company management. These programs generally result in asset impairments and workforce reductions in order to optimize the Company’s structure and facilitate improved long-term performance. Impairment charges are taken when the value-in-use of the asset is less than the asset’s carrying value. Workforce related charges are taken when an approved reorganization program is communicated to the relevant employee groups.

(ad) Reclassifications

Certain prior period amounts in the consolidated financial statements and accompanying notes have been reclassified to conform to the current period’s presentation. Most notably, the Company has presented transaction and integration-related expenses as a separate line in the Consolidated Statement of Operations and reclassified certain costs incurred in the years ended December 31, 2020 and December 31, 2019 within this line. These costs consist of transaction and integration-related expenses and contingent consideration valuation adjustments related to ICON's prior period acquisitions. These costs were previously presented in the selling, general and administrative expenses but have been reclassified to transaction and integration-related expenses to conform to the current period’s presentation.

Investments

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Investments

(a) Available for sale investments


	December 31, 2021		December 31, 2020
	(in thousands)
Available for sale investments at start of year	$	1,729	$	49,628

Purchases	480		—
Sales and maturities	(497)		(47,902)

Realized gain on sale of short term investments	—		234
Unrealized capital loss – investments	—		(231)
Available for sale investments at end of year	$	1,712	$	1,729

The Company classifies its investment in short term investments as available for sale. Short term investments comprise highly liquid investments with maturities of greater than three months and minimum "A-" rated fixed term deposits. Short term investments at December 31, 2021 have an average maturity of 2.7 years compared to 3.4 years at December 31, 2020.

The following table represents our available for sale short term investments by major security type as of December 31, 2021:


					Maturity by period
	Cost Total		Fair Value Total		Less than 1 year		1 to 5 years
	(in millions)


Term deposits	$	1.7	$	1.7	$	0.5	$	1.2
Total ($ in millions)	$	1.7	$	1.7	$	0.5	$	1.2

The contractual maturity of certain investments in the portfolio is greater than 12 months; however, classification as short-term investments reflects the Company practice and intention in respect of these investments. The Company recognizes the unrealized losses at fair value in equity as these unrealized losses on short term investments have been considered as temporary.

(b) Investments in equity - long termThe Company entered into subscription agreements with a number of funds. Capital totaling $16.9 million had been advanced under the terms of the subscription agreements at December 31, 2021 (December 31, 2020: $13.3 million). The Company determined that the interests in the funds meet the definition of equity securities without readily determinable fair values. The Company concluded that the interests held at December 31, 2021 qualify for the NAV practical expedient in ASC 820 'Fair value measurements and disclosures'. There was an increase in fair value of $3.2 million (December 31, 2020: $2.5 million) recognized in net income during the year bringing the carrying value of the subscriptions to $22.6 million at December 31, 2021 (December 31, 2020: $15.8 million). At December 31, 2021, the Company had committed to future investments of $17.4 million in respect of these funds.

The Company has invested $4.9 million to obtain a 49% interest in the voting share capital of Oncacare. The Company’s investment in Oncacare is accounted for under the equity method due to the Company's ability to exercise significant influence over Oncacare that is considered to be greater than minor. The Company records its pro rata share of the earnings/losses of this investment in 'Share of equity method investments' in the Consolidated Statement of Operations. See additional details in note 2 - Significant accounting policies.

The majority investor has the right to sell the 51% majority voting share capital exclusively to the Company in an eighteen month period, commencing January 1, 2023 and ICON also has the right to acquire the 51% majority voting share capital from August 1, 2025.

The following table represents our equity method investments at December 31, 2021:


	Ownership Percentage		Carrying Value		Carrying Value

	December 31, 2021		December 31, 2021		December 31, 2020
			(in thousands)
Oncacare Limited	49	%	$	2,373	$	4,534

The Company has recorded a loss of $2.2 million representing its pro rata share of the losses in Oncacare since December 31, 2020. From the date of initial investment to year ended December 31, 2020, the Company recorded a loss of $0.4 million. During the year ended December 31, 2021, the Company provided a loan of $10 million to Oncacare in order to fund the continued development of the business operations. The loan accrues annual interest at 1.6% and the loan is repayable on June 30, 2025. Oncacare continues to perform in line with expectations.

Goodwill

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill


	December 31, 2021		December 31, 2020
	(in thousands)
Opening goodwill	$	936,257	$	883,170
Current year acquisitions (note 6)	8,120,006		27,191
Prior period acquisition	—		123
Foreign exchange movement	(18,332)		25,773
Closing goodwill	$	9,037,931	$	936,257

The Company has made a number of strategic acquisitions since inception to enhance its capabilities and experience in certain areas of the clinical development process. Goodwill arising on acquisition represents the excess of the cost of acquired entities over the net amounts assigned to assets acquired and liabilities assumed.

The Company tests goodwill annually for impairment or whenever events occur which may indicate impairment. The results of the Company's goodwill impairment testing assessed at September 30, 2021 during the year ended December 31, 2021 provided no evidence of impairment and indicated the existence of sufficient headroom such that a reasonably possible change to the key assumptions used would be unlikely to result in an impairment of the related goodwill.

Intangible Assets

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets


	December 31, 2021		December 31, 2020
Cost	(in thousands)
Customer relationships	$	4,056,642	$	144,251
Order backlog	528,022		39,269
Trade names & brands	204,685		2,766
Patient database	170,525		2,552
Technology assets	121,507		11,173
Total cost	5,081,381		200,011

Accumulated amortization	(370,538)		(133,551)
Net book value	$	4,710,843	$	66,460

On July 1, 2021, ICON plc announced the completion of its Merger with PRA Health Sciences, Inc. The Merger resulted in the recognition of Customer relationships of $3,915.0 million, Order backlog of $490.0 million, Trade names of $202.0 million, Patient database of $168.0 million and Technology assets of $111.0 million. These assets will be amortized over their expected useful lives of between 3 and 23 years. The valuation and useful lives of these assets remains provisional at December 31, 2021. In total, $223.5 million has been amortized in the period since the date of acquisition.

On January 22, 2020 a subsidiary of the Company, ICON Investments Limited acquired 100% of the equity share capital of the MedPass Group. MedPass is the leading European medical device CRO, regulatory and reimbursement consultancy, that specializes in medical device development and market access. The acquisition of MedPass further enhances ICON’s Medical Device and Diagnostic Research services, through the addition of new regulatory and clinical capabilities in Europe. On acquisition, certain customer relationships and order backlog identified, which were valued at $11.7 million and $2.9 million respectively, were recognized and are being amortized over approximately 13 years and 3 years, the estimated period of benefit. In total, $2.0 million has been amortized in the period to December 31, 2021 relating to the acquisition.

Future intangible asset amortization expense for the years ended December 31, 2022 to December 31, 2026 is as follows:


	Year Ended December 31, 2021
	(in thousands)
2022	$	456,973
2023	454,235
2024	338,463
2025	222,191
2026	208,175
	$	1,680,037

Business combinations

12 Months Ended

Dec. 31, 2021

Business Combinations [Abstract]

Business combinations

PRA Health Sciences, Inc. - Merger Completion

On July 1, 2021 (the "Merger Date"), the Company completed the Acquisition of PRA by means of a merger whereby Indigo Merger Sub, Inc., a Delaware corporation and subsidiary of ICON, merged with and into PRA Health Sciences, Inc., the parent of the PRA Health Sciences Group ("the Acquisition" and "the Merger"). The combined Group has retained the name ICON and brought together approximately 38,000 (as at the Merger date) employees across the globe, creating one of the world’s most advanced healthcare intelligence and clinical research organization. The Merger was accounted for as a business combination using the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations.

The combined Company leverages its enhanced operations to transform clinical trials and accelerate biopharma customers’ commercial success through the development of much needed medicines and medical devices. The new ICON has a renewed focus on leveraging data, applying technology and accessing diverse patient populations to speed up drug development.

Upon completion of the Merger, pursuant to the terms of the Merger Agreement, PRA became a wholly owned subsidiary of the ICON Group. Under the terms of the Merger, PRA shareholders received per share $80 in cash and 0.4125 shares of ICON stock. The trading of PRA common stock on NASDAQ was suspended prior to market open on July 1, 2021.

In the year ended December 31, 2021, the Company incurred $198.3 million of Merger-related expenses which were accounted for separately from the business combination and expensed as incurred within the “Transaction and integration related” line item of the Consolidated Statement of Operations. These costs consist primarily of investment banker fees, advisory fees, legal costs, accounting and consulting fees, share-based compensation expense, and employee retention bonuses. Included in the $198.3 million of transaction and integration costs are acquisition related costs (as defined by ASC 805) of $57.1 million. These costs include finders fees; advisory, legal, accounting, valuation, and other professional or consulting fees.

The Company also incurred approximately $86.7 million of Merger-related financing fees which are included in the “Interest expense” line item in the Consolidated Statement of Operations for the year ended December 31, 2021. The Company deferred $76.2 million of financing costs incurred as a result of the Senior Secured Credit Facility and Senior Secured Notes. These costs will be amortized over the term of the related debt.

The purchase accounting associated with the PRA Merger remains ongoing and the Company continues to review the acquisition balance sheet. The Company expects to conclude the purchase accounting exercise by June 30, 2022.

The Merger Date fair value of the consideration transferred consisted of the following:


			(in thousands)
Fair value of cash consideration			5,308,646
Fair value of ordinary shares issued to acquiree stockholders			5,658,126
Fair value of replacement share-based awards issued to acquiree employees			209,399
Repayment of term loan obligations and accrued interest *			865,800
			12,041,971

* This represents the portion of PRA debt paid by ICON. PRA also paid $401.6 million from available cash to settle debt obligations that existed at the Merger Date.

The following table summarizes the preliminary allocation of the consideration transferred based on management’s estimates of Merger Date fair values of assets acquired and liabilities assumed, with the excess of the purchase price over the estimated fair values of the identifiable net assets acquired recorded as goodwill:


	July 1,
	2021
	(in thousands)
Cash and cash equivalents	$	259,971
Accounts receivable and unbilled revenue	934,308
Other current assets	125,156
Fixed assets	156,851
Operating lease right-of-use assets	177,345
Goodwill *	8,120,006
Intangible assets	4,886,000
Deferred tax assets	28,099
Other assets	35,391
Accounts payable	(50,259)
Accrued expenses and other current liabilities	(380,342)
Current portion of operating lease liabilities	(36,625)
Unearned revenue	(739,278)
Non-current portion of operating lease liabilities	(144,403)
Deferred tax liabilities	(1,126,952)
Other non-current liabilities	(203,297)

Net assets acquired	$	12,041,971

* The goodwill in connection with the Merger is primarily attributable to the assembled workforce of PRA and the expected synergies of the Merger. None of the goodwill recognized is expected to be deductible for income tax purposes.

The following table summarizes the preliminary estimates of the fair value of identified intangible assets and their respective useful lives as of the Merger Date (in thousands, except for estimated useful lives):


	Estimated Fair Value	Estimated Useful Life
Customer relationships	3,915,000	23 years
Order backlog	490,000	3 years
Trade names	202,000	3 years
Patient database	168,000	7 years
Technology assets	111,000	5 years
	4,886,000

Since July 1, 2021, PRA has earned revenue of $2,053.4 million and pre-tax net income of $169.9 million in the six months ended December 31, 2021.

Unaudited Supplemental Pro Forma Information

The following pro forma financial information was derived from the historical financial statements of the Company and PRA and presents the combined results of operations as if the Merger had occurred on January 1, 2020. The pro forma financial information is presented for comparative purposes only and is not necessarily indicative of the results that would have actually occurred had the Merger been completed on January 1, 2020. In addition, the pro forma financial information does not give effect to any anticipated cost savings, operating efficiencies or other synergies that may result from the Merger, or any estimated costs that have been or will be incurred by the Company to integrate the assets and operations of PRA. Consequently, actual future results of the Company will differ from the pro forma financial information presented below:


	Year Ended		Year ended
	December 31		December 31
	2021		2020
	(in thousands)
Revenue	$	7,462,000	$	5,980,653
Net income/(loss)	$	340,942	$	(149,658)

The pro forma adjustments primarily relate to the amortization of acquired intangible assets, interest expense and amortization of deferred financing costs related to the new financing arrangements. In addition, the pro forma net income for the year ended December 31, 2021 was adjusted to exclude certain Merger-related nonrecurring adjustments; these adjustments were included in the year ended December 31, 2020 giving effect to the Merger as if it had occurred on January 1, 2020. The nonrecurring Merger-related adjustments include transaction costs, share-based compensation expense related to the acceleration of share-based compensation awards and replacement share-based awards, and financing fees. The Merger-related adjustments were tax effected using the rates applicable to the jurisdictions where they arose.

Acquisitions – MedPass Group ("MedPass")

On January 22, 2020 a subsidiary of the Company, ICON Investments Limited acquired 100% of the equity share capital of the MedPass Group. MedPass is the leading European medical device CRO, regulatory and reimbursement consultancy, that specializes in medical device development and market access. The acquisition of MedPass further enhances ICON’s Medical Device and Diagnostic Research services, through the addition of new regulatory and clinical capabilities in Europe. The integration of MedPass’s services brings noted expertise in complex class 3 medical devices, interventional cardiology and structural heart devices. Accounting for the acquisition of MedPass was finalized in the period ended December 31, 2020.

The acquisition of MedPass has been accounted for as a business combination in accordance with ASC 805 'Business Combinations'. The Company has made an assessment of the fair value of assets acquired and liabilities assumed as at that date. The following table summarizes the Company’s fair values of the assets acquired and liabilities assumed:


	January 22,
	2020
	(in thousands)
Cash & cash equivalents	$	10,170
Property, plant and equipment	45
Operating right of use assets	539
Goodwill *	27,191
Customer relationships	11,725
Order backlog	2,883
Accounts receivable	3,033


Prepayments and other current assets	158
Accounts payable	(368)
Unearned revenue	(989)
Other liabilities	(2,202)
Current lease liabilities	(219)
Non-current lease liabilities	(320)
Non-current deferred tax liability	(4,090)

Net assets acquired	$	47,556

Cash outflows	$	46,992
Working capital adjustment paid	564
Contingent consideration **	—

Total consideration	$	47,556

* Goodwill represents the acquisition of an established workforce that specializes in medical device development and market access. None of the goodwill recognized is expected to be deductible for income tax purposes.

** The fair value of the contingent consideration was estimated at the date of acquisition as $Nil. Depending on performance of MedPass for the 12 month period ended December 31, 2020, the total consideration could have increased by a maximum of $6.7 million in contingent consideration. In January 2021, the contingent consideration was finalized and a value of $Nil was payable.

In finalizing the acquisition of MedPass in the 12 month period from acquisition, fair value adjustments were made which resulted in an increase in accounts receivable ($0.2 million) and unearned revenue ($0.8 million) and a decrease in operating right of use assets ($0.8 million), other liabilities ($0.8 million), current lease liabilities ($0.1 million), non-current lease liabilities ($0.7 million) and non-current deferred tax liability ($0.6 million). Customer relationship and order backlog assets were also finalized.

Since January 22, 2020, MedPass earned revenue of $13.2 million and net income of $2.5 million in the year ended December 31, 2020. The proforma effect of the MedPass acquisition if completed on January 1, 2019 would have resulted in revenue and net income for the fiscal years ended December 31, 2020 and December 31, 2019 as follows:


	Year Ended
	2020		2019
	(in thousands)
Revenue	$	2,798,180	$	2,820,796
Net income	$	332,521	$	377,485

Property, Plant and Equipment, net

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment, net


	December 31, 2021		December 31, 2020
	(in thousands)
Cost
Land	$	3,724	$	3,724
Building	82,017		90,139
Computer equipment and software	506,322		440,930
Office furniture and fixtures	107,507		91,933
Laboratory equipment	29,210		44,567
Leasehold improvements	70,123		32,261
Motor vehicles	65		160

	798,968		703,714
Less accumulated depreciation and asset write offs	(462,524)		(529,371)

Property, plant and equipment (net)	$	336,444	$	174,343

The Company regularly updates its register of property, plant and equipment and during the year ended December 31, 2021 and the year ended December 31, 2020, certain fully depreciated assets were written off as they were no longer used in the Company.

Other Liabilities

12 Months Ended

Dec. 31, 2021

Other Liabilities Disclosure [Abstract]

Other Liabilities


	December 31, 2021		December 31, 2020
	(in thousands)
General trade and overhead liabilities*	$	459,814	$	188,638
Personnel related liabilities	413,185		161,363
Operating lease liabilities (note 23)	49,949		24,334
Facility related liabilities	12,055		9,441
Other liabilities	7,204		8,726
Restructuring liabilities (note 15)	7,377		7,219
Short term government grants	45		48
	$	949,629	$	399,769

*includes amounts due to third parties in respect of accrued reimbursable investigator expenses of $323.6 million at December 31, 2021 and $138.2 million at December 31, 2020.

Non-Current Other Liabilities

12 Months Ended

Dec. 31, 2021

Payables and Accruals [Abstract]

Non-Current Other Liabilities


	December 31, 2021		December 31, 2020
	(in thousands)
Defined benefit pension obligations, net (note 10)	$	16,262	$	10,395
Other non-current liabilities	25,599		15,971
	$	41,861	$	26,366

Employee Benefits

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Employee Benefits

Defined contribution or profit sharing style plans ("the Plans") are offered globally in a number of countries. In some cases, these plans are required by local laws or regulations. Certain Company employees are eligible to participate in the Plans and participants in the Plans may elect to defer a portion of their pre-tax earnings into a pension plan, which is run by an independent party. The Company matches participant's contributions up to certain levels of the participant's annual compensation. Contributions to the plan are recorded as an expense in the selling, general and administrative line in the Consolidated Statement of Operations.

The Company's United States operations maintain retirement plans (the "U.S. Plans") that qualify as a deferred salary arrangement under Section 401(k) of the Internal Revenue Code. Participants in the U.S. Plans may elect to defer a portion of their earnings, up to the Internal Revenue Service annual contribution limit. The Company matches participant's contributions at varying amounts, subject to a maximum of 4.5% of the participant's annual compensation. Contributions to this U.S. Plan are recorded, in the year contributed, as an expense in the Consolidated Statement of Operations. Contributions for the years ended December 31, 2021, December 31, 2020 and December 31, 2019 were $23.7 million, $17.0 million and $16.5 million respectively.

The Company maintains various retirement plans across the Group, many of which are required by local employment laws. In addition to the specific defined benefit schemes shown separately below, the Company maintains several other retirement plans with a total net obligation associated with these schemes of $8.0 million. This balance has been recorded in non-current other liabilities on the Consolidated Balance Sheet.

ICON Development Solutions Limited pension plan

One of the Company's subsidiaries, ICON Development Solutions Limited, operates a defined benefit pension plan in the United Kingdom for its employees. The plan is managed externally and the related pension costs and liabilities are assessed in accordance with the advice of a professionally qualified actuary. Plan assets at December 31, 2021, December 31, 2020 and December 31, 2019, consist of units held in independently administered funds. The pension costs of this plan are presented in the following tables in accordance with the requirements of ASC 715-60 'Defined Benefit Plans – Other Postretirement'. The plan has been closed to new entrants with effect from July 1, 2003.


Funded status	December 31, 2021		December 31, 2020
	(in thousands)
Projected benefit obligation	$	(41,813)	$	(43,988)
Fair value of plan assets	36,198		34,612
Funded status	$	(5,615)	$	(9,376)
Non-current other liabilities (note 9)	$	(5,615)	$	(9,376)


Change in benefit obligation	December 31, 2021		December 31, 2020
	(in thousands)
Benefit obligation at beginning of year	$	43,988	$	37,036
Service cost	134		100
Interest cost	665		746
Plan participants' contributions	23		22

Benefits paid	(489)		(724)
Actuarial (gain)/loss	(2,097)		5,294
Foreign currency exchange rate changes	(411)		1,514
Benefit obligation at end of year	$	41,813	$	43,988


Change in plan assets	December 31, 2021		December 31, 2020
	(in thousands)
Fair value of plan assets at beginning of year	$	34,612	$	32,016
Actual return on plan assets	2,347		2,092
Employer contributions	91		109
Plan participants' contributions	23		22
Benefits paid	(489)		(724)
Foreign currency exchange rate changes	(386)		1,097
Fair value of plan assets at end of year	$	36,198	$	34,612

The fair values of the assets above do not include any of the Company's own financial instruments, property occupied by, or other assets used by, the Company.

The following amounts were recorded in the Consolidated Statement of Operations as components of the net periodic benefit cost:


	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Service cost	$	134	$	100	$	107
Interest cost	665		746		867
Expected return on plan assets	(1,171)		(1,214)		(574)
Amortization of net loss	625		160		67

Net periodic benefit cost	$	253	$	(208)	$	467

The following assumptions were used at the commencement of the year in determining the net periodic pension benefit cost for the years ended December 31, 2021, December 31, 2020 and December 31, 2019:


	December 31, 2021		December 31, 2020		December 31, 2019
Discount rate	1.5	%	2.1	%	2.9	%
Rate of compensation increase	3.4	%	3.3	%	3.7	%
Expected rate of return on plan assets	3.4	%	4.0	%	2.1	%


Other comprehensive income	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Actuarial (gain)/loss - benefit obligation	$	(2,097)	$	5,294	$	4,756
Actuarial gain – plan assets	(1,176)		(878)		(2,930)
Actuarial loss recognized in net periodic benefit cost	(625)		(160)		(67)
Total	$	(3,898)	$	4,256	$	1,759

The estimated net loss and prior service cost for the defined benefit pension plan that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year are $0.2 million and $Nil respectively.

Benefit Obligation

The following assumptions were used in determining the benefit obligation at December 31, 2021 and December 31, 2020:


	December 31, 2021		December 31, 2020
Discount rate	1.8	%	1.5	%
Rate of compensation increase	3.7	%	3.4	%

A single discount rate is used which, when used to discount the projected benefit cash flows underlying a pension scheme with a 26 year duration, gives the same result as a full AA corporate bond yield curve.

Actuarial gains on the benefit obligation during 2021 resulted from changes in the assumptions compared to those adopted at December 2020. Changes in the assumptions reflect the changes in market conditions from December 2020 to December 2021 and the actuarial gain is primarily due to the change in the discount rate.

Plan Assets

The assets of the scheme are held on an investment platform with Mobius which invests in a number of investment funds with Legal & General, Stone Harbor, Ninety-One and Barings. The overall investment strategy is that approximately 20% of investments are in senior secured loans, 18% in corporate bonds, 19% in high yield bonds and multi-asset credit fund and 24% in world equities respectively. There is no self-investment in employer related assets. The expected long-term rate of return on assets at December 31, 2021 of 3.8% was calculated as the value of the fund after application of a market value reduction factor. The expected long term rates of return on different asset classes are as follows:


Expected long-term return per annum	December 31, 2021		December 31, 2020
Corporate Bonds (including 50% high yield bonds)	2.8	%	2.8	%
Equities	5.5	%	5.2	%
Secured Loans and Multi Asset Credit	3.0	%	3.0	%

The long-term expected rate of return on cash is determined by reference to traditional corporate bond rates at the latest Balance Sheet date. The long-term expected returns on traditional corporate and government bonds are determined by reference to corporate bond yields and gilt yields respectively at the Balance Sheet date. The long-term expected returns on equities are based on the rate of return on government bonds with an allowance for out-performance. The long-term expected return on high yield bonds, secured loans and multi asset credit is based on the return on traditional corporate bonds with an allowance for out-performance.

The underlying asset split of the fund is shown below.


Asset Category	December 31, 2021		December 31, 2020
Corporate Bonds (including 50% high yield bonds)	37	%	40	%
Equities	24	%	21	%
Secured Loans and Multi Asset Credit	39	%	39	%


	100	%	100	%

Applying the above expected long term rates of return to the asset distribution at December 31, 2021, gives rise to an expected overall rate of return of scheme assets of approximately 3.8% per annum.

Plan Asset Fair Value Measurements


	Quoted Prices in Active Markets for Identical Assets Level 1
	December 31, 2021		December 31, 2020
	(in thousands)
Cash	$	162	$	11
Fixed Income Securities
L&G Life GPBF All World Equity Index Fund	8,743		7,460
L&G Life DC Active Corporate Bond	6,409		6,797
Stone Harbor High Yield Bond Fund	6,965		6,861
Ninety One Global Total Return Credit	3,435		3,472

Stone Harbor Multi Asset Credit Portfolio	3,359		3,389
Barings European Loan Fund Buy & Hold	7,125		6,622
	$	36,198	$	34,612

Cash Flows

The Company expects to contribute $0.1 million to the pension fund in the year ending December 31, 2022.

The following annual benefit payments, which reflect expected future service as appropriate, are expected to be paid.


	(in thousands)
2022	$	256
2023	340
2024	417
2025	453
2026	788
Years 2027 - 2031	3,859

The expected cash flows are estimated figures based on the members expected to retire over the next 10 years assuming no early retirements, withdrawals or commutation of pension for cash. At the present time it is not clear whether annuities will be purchased when members reach retirement or whether pensions will be paid each month out of scheme assets. The cash flows above have been estimated on the assumption that pensions will be paid monthly out of scheme assets. If annuities are purchased, then the expected benefit payments will be significantly different from those shown above.

Aptiv Solutions pension plan

On May 7, 2014 the Company acquired 100% of the common stock of Aptiv Solutions ("Aptiv"). The acquisition of Aptiv was accounted for as a business combination in accordance with ASC 805 'Business Combinations'. The Company has a defined benefit plan covering its employees in Switzerland as mandated by the Swiss government. Benefits are based on the employee's years of service and compensation. Benefits are paid directly by the Company when they become due, in conformity with the funding requirements of applicable government regulations. The plan is managed externally and the related pension costs and liabilities are assessed in accordance with the advice of a professionally qualified actuary. Plan assets at December 31, 2021 and December 31, 2020 consist of units held in independently administered funds. The pension costs of this plan are presented in the following tables in accordance with the requirements of ASC 715-60 'Defined Benefit Plans – Other Postretirement'.


Funded status	December 31, 2021		December 31, 2020
	(in thousands)
Projected benefit obligation	$	(7,643)	$	(8,620)
Fair value of plan assets	6,964		7,601
Funded status	$	(679)	$	(1,019)
Non-current other liabilities (note 9)	$	(679)	$	(1,019)


Change in benefit obligation	December 31, 2021		December 31, 2020
	(in thousands)
Benefit obligation at beginning of year	$	8,620	$	7,047
Service cost	150		139
Interest cost	12		21
Plan participants' contributions	95		81
Settlement	(483)		—
Prior service cost	(82)		(23)
Transferred balances	76		245
Actuarial (gain)/ loss	(484)		406
Foreign currency exchange rate changes	(261)		704
Benefit obligation at end of year	$	7,643	$	8,620


Change in plan assets	December 31,		December 31,
	2021		2020
	(in thousands)
Fair value of plan assets at beginning of year	$	7,601	$	6,014
Expected return on plan assets	15		21
Actual return on plan assets	(238)		519
Scheme contributions	128		105
Plan participants' contributions	95		81
Transferred balances	76		245
Settlement	(483)		—
Foreign currency exchange rate changes	(230)		616
Fair value of plan assets at end of year	$	6,964	$	7,601

The fair values of the assets above do not include any of the Company's own financial instruments, property occupied by, or other assets used by, the Company.

PRA Switzerland AG pension plan

On July 1, 2021, the Company completed the Acquisition of PRA. PRA Switzerland AG, a subsidiary of the Company has a defined benefit plan covering its employees in Switzerland as mandated by the Swiss government. Benefits are based on the employee's years of service and compensation. Benefits are paid directly by the Company when they become due, in conformity with the funding requirements of applicable government regulations. The plan is managed externally and the related pension costs and liabilities are assessed in accordance with the advice of a professionally qualified actuary. Plan assets at December 31, 2021 consist of units held in independently administered funds. The pension costs of this plan are presented in the following tables in accordance with the requirements of ASC 715-60 'Defined Benefit Plans – Other Postretirement'.


Funded status	December 31, 2021
	(in thousands)
Projected benefit obligation	$	(4,990)
Fair value of plan assets	3,017
Funded status	$	(1,973)
Non-current other liabilities (note 9)	$	(1,973)


Change in benefit obligation	December 31, 2021
	(in thousands)
Benefit obligation as at July 1, 2021	$	4,890
Service cost	207
Interest cost	19
Plan participants’ contributions	135


Transferred benefits paid	(113)
Actuarial loss	1
Foreign currency exchange rate changes	(149)
Benefit obligation at end of year	$	4,990


Change in plan assets	December 31,
	2021
	(in thousands)
Fair value of plan assets at as at July 1, 2021	$	2,849
Expected return on plan assets	15

Scheme contributions	135
Plan participants’ contributions	135
Transferred benefits paid	(113)

Foreign currency exchange rate changes	(4)
Fair value of plan assets at end of year	$	3,017

The fair values of the assets above do not include any of the Company's own financial instruments, property occupied by, or other assets used by, the Company.

- Definition

The entire disclosure for retirement benefits.

+ References

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+ Details

Equity Incentive Schemes and Stock Compensation Charges

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Equity Incentive Schemes and Stock Compensation Charges

Share Options

On July 21, 2008 the Company adopted the Employee Share Option Plan 2008 (the "2008 Employee Plan") pursuant to which the Compensation and Organization Committee of the Company's Board of Directors may grant options to any employee, or any Director holding a salaried office or employment with the Company or a Subsidiary for the purchase of ordinary shares. On the same date, the Company also adopted the Consultants Share Option Plan 2008 (the "2008 Consultants Plan"), pursuant to which the Compensation and Organization Committee of the Company's Board of Directors may grant options to any consultant, adviser or non-executive Director retained by the Company or any Subsidiary for the purchase of ordinary shares.

On February 14, 2017 both the 2008 Employee Plan and the 2008 Consultants Plan (together the "2008 Option Plans") were amended and restated in order to increase the number of options that can be issued under the 2008 Consultants Plan from 0.4 million to 1.0 million and to extend the date for options to be granted under the 2008 Option Plans.

An aggregate of 6.0 million ordinary shares have been reserved under the 2008 Employee Plan, as reduced by any shares issued or to be issued pursuant to options granted under the 2008 Consultants Plan, under which a limit of 1.0 million shares applies. Further, the maximum number of ordinary shares with respect to which options may be granted under the 2008 Employee Option Plan, during any calendar year to any employee shall be 0.4 million ordinary shares. There is no individual limit under the 2008 Consultants Plan. No options may be granted under the 2008 Option Plans after February 14, 2027.

Each option granted under the 2008 Option Plans will be an employee stock option, or NSO, as described in Section 422 or 423 of the Internal Revenue Code. Each grant of an option under the 2008 Options Plans will be evidenced by a Stock Option Agreement between the optionee and the Company. The exercise price will be specified in each Stock Option Agreement, however option prices will not be less than 100% of the fair market value of an ordinary share on the date the option is granted.

On January 17, 2003 the Company adopted the Share Option Plan 2003 (the "2003 Share Option Plan") pursuant to which the Compensation and Organization Committee of the Board could grant options to officers and other employees of the Company or its subsidiaries for the purchase of ordinary shares. An aggregate of 6.0 million ordinary shares were reserved under the 2003 Share Option Plan; and in no event could the number of ordinary shares issued pursuant to options awarded under this plan exceed 10% of the outstanding shares, as defined in the 2003 Share Option Plan, at the time of the grant, unless the Board expressly determined otherwise. Further, the maximum number of ordinary shares with respect to which options could be granted under the 2003 Share Option Plan during any calendar year to any employee was 0.4 million ordinary shares. The 2003 Share Option Plan expired on January 17, 2013. No new options may be granted under this plan.

Share option awards are granted with an exercise price equal to the market price of the Company's shares at date of grant. Prior to 2018, share options typically vest over a period of five years from date of grant and expire eight years from date of grant. Share options granted to non-executive directors from 2018 vest over 12 months and expire eight years from the date of grant.

Legacy PRA Equity Incentive Plans

The following represent the legacy PRA equity incentive plans, which still have equity outstanding but have been terminated as of July 1, 2021, as to grants of future awards.

Pursuant to the Merger Agreement, effective on July 1, 2021, each outstanding stock option and restricted stock unit under the PRA Plans was assumed by the Company and converted into a stock option or Restricted Share Unit exercisable for or payable in Ordinary Shares based on the ratio of the average trading price per Ordinary Share for the ten days prior to July 1, 2021, and the corresponding value of the Merger consideration for each PRA Share. Accordingly, the plans as detailed below were assumed by the Company.

PRA Health Sciences, Inc. 2020 Stock Incentive Plan was amended and restated and assumed by the Registrant effective as of July 1, 2021. The 2020 Stock Incentive Plan (“the 2020 Plan”), was approved by the PRA stockholders at their annual meeting on May 18, 2020. The 2020 Plan allowed for the issuance of stock options, stock appreciation rights, restricted shares and restricted stock units, other stock-based awards, and performance compensation awards as permitted by applicable laws. The 2020 Plan authorized the issuance of 2,500,000 shares of common stock plus all shares that remained available under the prior plan on May 18, 2020.

The PRA Health Sciences, Inc. 2018 Stock Incentive Plan was amended and restated and assumed by the Company effective as of July 1, 2021. The 2018 Stock Incentive Plan (the “2018 Plan”), was approved by the PRA stockholders at their annual meeting on May 31, 2018. The 2018 Plan allowed for the issuance of stock options, stock appreciation rights, restricted shares and restricted stock units, other stock-based awards, and performance compensation awards as permitted by applicable laws. The 2018 Plan authorized the issuance of 2,000,000 shares of common stock plus all shares that remained available under the 2014 Plan on May 31, 2018 (which included shares carried over from the 2013 Plan).

The PRA Health Sciences, Inc. 2014 Omnibus Incentive Plan was amended and restated and assumed by the Company effective as of July 1, 2021 (the “2014 Plan”). On November 23, 2014, the PRA Health Sciences, Inc. Board of

Directors approved the formation of the 2014 Plan for Key PRA Employees. The 2014 Plan allowed for the issuance of stock options, stock appreciation rights, restricted shares and restricted stock units, other stock-based awards, and performance compensation awards as permitted by applicable laws.

The 2013 Stock Incentive Plan for Key Employees of PRA Health Sciences and its Subsidiaries was amended and restated and assumed by the Registrant effective as of July 1, 2021 (the “2013 Plan”). On September 23, 2013, the PRA Health Sciences, Inc. Board of Directors approved the formation of the 2013 Plan for Key Employees of Pinnacle Holdco Parent, Inc. and its subsidiaries. The 2013 Plan allowed for the issuance of stock options and other stock-based awards as permitted by applicable laws. The number of shares available for grant under the 2013 Plan was 12.5% of the outstanding shares at closing on a fully diluted basis. The 2013 Plan authorized the issuance of 2,052,909 shares of common stock.

The following table summarizes the transactions for the Company's share option plans for the years ended December 31, 2021, December 31, 2020 and December 31, 2019:


	Options Granted Under Plans	Weighted Average Exercise Price
Outstanding at December 31, 2018	920,746	$	74.32
Granted	97,112	$	140.13
Exercised	(329,870)	$	65.54
Canceled	(31,881)	$	88.12
Outstanding at December 31, 2019	656,107	$	87.80
Granted	107,737	$	159.83
Exercised	(193,417)	$	68.19
Canceled/expired	(16,681)	$	92.21
Outstanding at December 31, 2020	553,746	$	108.53
Assumed through business combinations *	2,177,130	$	108.78
Granted	100,299	$	177.76
Exercised	(1,065,529)	$	111.29
Canceled/expired	(70,186)	$	128.46
Outstanding at December 31, 2021	1,695,460	$	104.79
Vested and exercisable at December 31, 2021	989,419	$	91.70

*Represents stock options issued as replacement awards in connection with the Merger.

The weighted average remaining contractual life of options outstanding and options exercisable at December 31, 2021, was 5.39 years and 4.55 years respectively (2020: 4.86 years and 3.60 years respectively).

Outstanding and exercisable share options:

The following table summarizes information concerning outstanding and exercisable share options as of December 31, 2021:


Options Outstanding					Options Exercisable
Range Exercise Price	Number of Shares	Weighted Average Remaining Contractual Life	Weighted Average Exercise Price		Number of Shares	Weighted Average Exercise Price

14.80 - 97.30	638,118	3.45			605,624
103.81 - 124.00	320,310	6.49			130,920
125.74 - 147.26	540,296	6.56			235,808
159.33 - 231.08	196,736	6.68			17,067

14.80 - 231.08	1,695,460	5.39	$	104.79	989,419	$	91.70

Options outstanding include both vested and unvested options as at December 31, 2021. Options exercisable represent options which have vested at December 31, 2021. From the date of grant, substantially all options vest over a five to eight year period.

Fair value of Stock Options Assumptions

The weighted average fair value of options granted during the years ended December 31, 2021, December 31, 2020 and December 31, 2019 was calculated using the Black-Scholes option pricing model. The weighted average fair values and assumptions were as follows:


	Year Ended
	December 31, 2021			December 31, 2020			December 31, 2019
Weighted average fair value	$	49.15		$	42.43		$	43.43

Assumptions:
Expected volatility	30		%	30		%	30		%
Dividend yield	—		%	—		%	—		%
Risk-free interest rate	0.78		%	0.57		%	2.55		%
Expected life	5.0 years			5.0 years			5.0 years

The weighted average fair value of options assumed on the date of the Merger was calculated using the Black-Scholes option pricing model. The weighted average fair values on the date of the Merger and assumptions used were as follows:


	July 1, 2021
Weighted average grant date fair value	$	107.21
Assumptions:
Expected volatility	30		%
Dividend yield	—		%
Risk-free interest rate	0.56		%
Expected life	3.5 years

Expected volatility is based on the historical volatility of our common stock over a period equal to the expected term of the options; the expected life represents the weighted average period of time that options granted are expected to be outstanding given consideration to vesting schedules and our historical experience of past vesting and termination patterns. The risk-free rate is based on the U.S. government zero-coupon bonds yield curve in effect at time of the grant for periods corresponding with the expected life of the option.

Restricted Share Units and Performance Share Units

On April 23, 2013 the Company adopted the 2013 Employees Restricted Share Unit and Performance Share Unit Plan (the "2013 RSU Plan") pursuant to which the Compensation and Organization Committee of the Company's Board of Directors may select any employee, or any Director holding a salaried office or employment with the Company, or a Subsidiary to receive an award under the plan. On May 11, 2015 the 2013 RSU Plan was amended and restated in order to increase the number of shares that can be issued under the RSU Plan by 2.5 million shares. Accordingly, an aggregate of 4.1 million ordinary shares have been reserved for issuance under the 2013 RSU Plan. The shares are awarded at par value and vest over a service period. Awards under the 2013 RSU Plan may be settled in cash or shares at the option of the Company.

On April 30 2019, the Company approved the 2019 Consultants and Directors Restricted Share Unit Plan (the “2019 Consultants RSU Plan”), which was effective as of May 16, 2019, pursuant to which the Compensation and Organization Committee of the Company’s Board of Directors may select any consultant, adviser or non-executive Director retained by the Company, or a Subsidiary to receive an award under the plan. 250,000 ordinary shares have been reserved for issuance under the 2019 Consultants RSU Plan. The awards are at par value and vest over a service period. Awards granted to non-executive directors during 2020 and 2021 vest over twelve months.

The Company has awarded RSUs and PSUs to certain key individuals of the Group. The following table summarizes RSU and PSU activity for the year ended December 31, 2021:


	PSU Outstanding Number of Shares	PSU Weighted Average Grant Date Fair Value		RSU Outstanding Number of Shares	RSU Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020	159,641	$	137.64	341,424	$	145.77

Assumed through business combination*	—	$	—	589,517	$	206.71
Granted	55,444	$	177.77	171,316	$	214.36
Shares vested **	(44,132)	$	115.61	(446,404)	$	186.99
Forfeited	(16,763)	$	141.36	(83,068)	$	188.49

Outstanding at December 31, 2021	154,190	$	160.23	572,785	$	191.20

* Represents restricted stock units issued as replacement awards in connection with the Merger.

** Includes 161,389 RSU's which vested on the date of the Merger.

The fair value of RSUs vested for the year ended December 31, 2021 totaled $83.5 million (2020: $14.3 million). The share price range for the year was $115.11 - $206.71 (2020: $83.47 - $156.21).

The fair value of PSUs vested for the year ended December 31, 2021 totaled $5.1 million (2020: $5.3 million). The share price range for the year was $115.11 - $125.74 (2020: $83.47 - $90.03).

The PSUs vest based on service and specified EPS targets over the period 2019 – 2021, 2020 – 2022 and 2021 – 2023. Depending on the actual amount of EPS from 2019 to 2023, up to an additional 71,890 PSUs may also be granted.

Non-cash stock compensation expense

Income from operations for the year ended December 31, 2021 is stated after charging $133.8 million in respect of non-cash stock compensation expense. Non-cash stock compensation expense has been allocated as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Direct costs	$	18,551	$	8,557	$	14,777
Selling, general and administrative	41,457		17,714		12,042
Transaction and integration related *	73,836		—		—
Total compensation costs	$	133,844	$	26,271	$	26,819

* Represents the post combination portion of the accelerated vesting of awards following the completion of the Merger

The income tax expense for the year ended December 31, 2021 reflects a net income tax benefit of $22.7 million in connection with stock compensation (including excess tax benefits) and the total tax benefit in connection with stock options exercised during 2021 was $23.9 million. The income tax expense for the year ended December 31, 2020 reflects a net income tax benefit of $6.9 million in connection with stock compensation (including excess tax benefits) and the total tax benefit in connection with stock options exercised during 2020 was $2.5 million. The income tax expense for the year ended December 31, 2019 reflects a net income tax benefit of $8.2 million in connection with stock compensation (including excess tax benefits) and the total tax benefit realized in connection with stock options exercised during 2019 was $1.9 million.

Share Capital	12 Months Ended
Share Capital	Dec. 31, 2021
Equity [Abstract]
Share Capital	Share Capital Holders of ordinary shares will be entitled to receive such dividends as may be recommended by the Board of Directors of the Company and approved by the shareholders and/or such interim dividends as the Board of Directors of the Company may decide. On liquidation or a winding up of the Company, the par value of the ordinary shares will be repaid out of the assets available for distribution among the holders of the ordinary shares of the Company. Holders of ordinary shares have no conversion or redemption rights. On a show of hands, every holder of an ordinary share present in person or proxy at a general meeting of shareholders shall have one vote, for each ordinary share held with no individual having more than one vote. On July 1, 2021, the Company completed the Acquisition of PRA. In accordance with the terms of the Merger Agreement, the Company issued 27,372,427 shares of the Company’s ordinary share capital at par value in exchange for all outstanding PRA shares of common stock. During the year ended December 31, 2021, 1,065,529 options were exercised by employees at an average exercise price of $111.29 per share for total proceeds of $118.6 million. During the year ended December 31, 2021, 446,404 ordinary shares were issued in respect of certain RSUs and 44,132 ordinary shares were issued in respect of PSUs previously awarded by the Company. During the year ended December 31, 2020, 193,417 options were exercised by employees at an average exercise price of $68.19 per share for total proceeds of $13.2 million. During the year ended December 31, 2020, 144,172 ordinary shares were issued in respect of certain RSUs and 63,516 ordinary shares were issued in respect of PSUs previously awarded by the Company. During the year ended December 31, 2019, 329,870 options were exercised by employees at an average exercise price of $65.54 per share for total proceeds of $21.6 million. During the year ended December 31, 2019, 237,119 ordinary shares were issued in respect of certain RSUs and 118,611 ordinary shares were issued in respect of PSUs previously awarded by the Company. (a)Share Repurchase Program There were no share buybacks in the year ended December 31, 2021. A resolution was passed at the Company’s Annual General Meeting (“AGM”) on July 22, 2016, which authorized the Directors to purchase (buyback) up to 10% of the outstanding shares in the Company. This authorization was renewed at the Company's AGM on each of July 25, 2017, July 24, 2018, July 23, 2019, July 21, 2020 and July 20, 2021. On October 3, 2016, the Company commenced a share buyback program of up to $400 million. The share buyback program was completed during the year ended December 31, 2018 with a total of 4,026,576 ordinary shares redeemed for a total consideration of $372.1 million. On January 8, 2019, the Company commenced a further share buyback program of up to 1.0 million ordinary shares which was completed during the year ended December 31, 2019. These shares were redeemed by the Company for a total consideration of $141.6 million. On October 22, 2019, the Company commenced a further share buyback program. At December 31, 2019, 35,100 ordinary shares were redeemed by the Company for a total consideration of $5.3 million. During the year ended December 31, 2020, 1,235,218 ordinary shares were redeemed by the Company under this buyback program for a total consideration of $175.0 million. All ordinary shares that were redeemed under the buyback program were canceled in accordance with the Constitution of the Company and the nominal value of these shares transferred to other undenominated capital as required under Irish Company law. Under the repurchase program, a broker purchased or may purchase the Company's shares from time to time on the open market or in privately negotiated transactions in accordance with agreed terms and limitations. The program was and may be in the future designed to allow share repurchases during periods when the Company would ordinarily not be permitted to do so because it may be in possession of material non-public or price-sensitive information or due to applicable insider trading laws or self-imposed trading blackout periods. The Company's instructions to the broker in such cases were or may in the future be irrevocable and the trading decisions in respect of the repurchase program were made or will be made independently of and uninfluenced by the Company. The Company confirms that on entering the share repurchase plans it had no material non-public, price-sensitive or inside information regarding the Company or its securities. Furthermore, the Company will not enter into additional plans whilst in possession of such information. The timing and actual number of shares acquired by way of the redemption will be dependent on market conditions, legal and regulatory requirements and the other terms and limitations contained in the program. In addition, acquisitions under the program may be suspended or discontinued in certain circumstances in accordance with the agreed terms. Therefore, there can be no assurance as to the timing or number of shares that may be acquired under the program.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

The Company's United States and Irish based subsidiaries file income tax returns in the United States and Ireland respectively. Other foreign subsidiaries are taxed separately under the laws of their respective countries.

The components of income before income tax expense are as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Ireland	$	231,893	$	280,310	$	323,726
United States	(278,413)		41,950		21,073
Other	243,200		58,945		82,190
Income before income tax expense	$	196,680	$	381,205	$	426,989

The components of income tax expense are as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Income tax expense:
Current tax expense:
Ireland	$	18,469	$	28,963	$	35,955
United States	35,478		3,022		5,073
Other	48,003		14,963		11,642
Total current tax expense	101,950		46,948		52,670

Deferred tax (benefit)/expense:
Ireland	553		1,654		2,833
United States	(52,717)		4,577		(3,502)
Other	(8,452)		(5,304)		(868)
Total deferred tax (benefit)/expense	(60,616)		927		(1,537)

Income tax expense allocated to continuing operations	41,334		47,875		51,133

Income tax expense was allocated to the following components of other comprehensive income:

Currency impact on long term funding	49		68		25


Total	$	41,383	$	47,943	$	51,158

Ireland's statutory income tax rate is 12.5%. The Company's consolidated reported income tax expense differed from the amount that would result from applying the Irish statutory rate as set forth below:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Taxes at Irish statutory rate of 12.5% (2021:12.5%; 2020:12.5%)	$	24,586	$	47,651	$	53,374
Foreign and other income taxed at higher rates	20,045		7,943		7,356
Research & development tax incentives	(3,120)		(1,243)		(893)
Movement in valuation allowance	3,101		3,581		(10)
Effects of change in tax rates	(128)		108		359
Change in unrecognized tax benefits	5,246		(1,672)		(1,273)
Impact of stock compensation	(9,083)		(5,150)		(7,383)

Other	687		(3,343)		(397)
Income tax expense	$	41,334	$	47,875	$	51,133

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and deferred tax liabilities are presented below:


	December 31, 2021		December 31, 2020
	(in thousands)
Deferred tax liabilities:
Property, plant and equipment	$	19,606	$	1,359
Right-of-use-assets	33,449		9,402
Goodwill	33,354		31,629
Intangible assets	1,201,086		13,398
Other	1,761		1,009
Total deferred tax liabilities recognized	1,289,256		56,797

Deferred tax assets:
Operating loss and tax credits carryforwards	86,893		42,794
Property, plant and equipment	5,846		6,040
Lease liabilities	36,106		9,394
Intangible assets	4,596		—
Accrued expenses and unbilled revenue	69,198		24,368
Stock compensation	25,557		3,672
Deferred compensation	3,445		3,184
Unearned revenue	64,924		2,257
Other	602		155
Total deferred tax assets	297,167		91,864
Valuation allowance for deferred tax assets	(45,495)		(32,768)
Deferred tax assets recognized	251,672		59,096
Overall net deferred tax asset/(liability)	$	(1,037,584)	$	2,299

At December 31, 2021 Ireland subsidiaries had tax credit carryforwards for income tax purposes that may be carried forward indefinitely, available for offset against future tax liabilities, if any, of $14.0 million.

At December 31, 2021 U.S. subsidiaries had U.S. federal and state net operating loss ("NOL") carryforwards of approximately $10.3 million and $297.0 million, respectively. These NOLs are available for offset against future taxable income and the expiry dates are shown in the table below. Of the $10.3 million U.S. federal NOLs, approximately $5.0 million is available for offset against future U.S. federal taxable income in 2022. The subsidiaries' ability to use the remaining U.S. federal and state NOL carryforwards is limited on an annual basis due to change of ownership in 2014, 2017, and 2019, as defined by Section 382 of the Internal Revenue Code of 1986, as amended. Of the U.S. federal NOLs, $10.3 million are limited by Section 382 as follows: $10.2 million for the years 2022 - 2035 and $0.1 million in 2036 - 2040. As at December 31, 2021, U.S subsidiaries also had disallowed interest carryforwards of $145.7 million that can be carried forward indefinitely. These carryforwards are available for offset against future taxable income in the event that the U.S subsidiaries have excess capacity for interest deductions in future years.

At December 31, 2021 other than those in the U.S. and Ireland, we had operating loss carryforwards for income tax purposes that may be carried forward indefinitely, available to offset against future taxable income, if any, of approximately $42.3 million. At December 31, 2021 those subsidiaries also had additional operating loss carryforwards of $19.9 million which are due to expire between 2022 and 2028 and operating loss carryforwards of $19.9 million which are due to expire between 2029 and 2038. In addition, at December 31, 2021 those subsidiaries had tax credit carryforwards for income tax purposes that may be carried forward indefinitely, available to offset against future tax liabilities, if any, of $5.3 million.

The expected expiry dates of these US losses are as follows:


	Federal NOL's		State NOL's
	(in thousands)
2022-2035	$	10,238	$	227,538
2036-2040	16		25,073
Indefinite	95		44,370

	$	10,349	$	296,981

In addition, we also have general business tax credit carryforwards of approximately $0.8 million that are available to reduce future U.S. federal and state income taxes. The general business tax credits are non-refundable and are due to expire between the years 2026-2038.

The valuation allowance at December 31, 2021 was approximately $45.5 million. The valuation allowance for deferred tax assets as of December 31, 2020 and December 31, 2019 was $32.8 million and $27.7 million respectively. The net change in the total valuation allowance was an increase of $12.8 million during 2021 and an increase of $5.1 million during 2020. Of the total increase of $12.8 million in 2021, $9.3 million was in respect of acquired entity, $4.4 million was recognized within income tax expense and a decrease of $0.9 million was recognized in Other Comprehensive Income. Of the total increase of $5.1 million in 2020, $3.6 million resulted in a current year income tax expense, and $1.5 million was recognized in Other Comprehensive Income.

The valuation allowances at December 31, 2021 and December 31, 2020 were primarily related to operating losses and tax credits carried forward that, in the judgment of management, are not more likely than not to be realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, loss utilization, projected future taxable income and mitigation strategies in making this assessment. In respect of deferred tax assets not subject to a valuation allowance, management considers that it is more likely than not that these deferred tax assets will be realized on the basis that there will be sufficient reversals of deferred tax liabilities and taxable income in future periods.

The Company has recognized a deferred tax liability of $0.8 million (2020: $0.9 million) for investments in foreign subsidiaries where the Company does not consider the earnings to be indefinitely reinvested. For the deferred tax liability not recognized in respect of temporary differences related to investments in foreign subsidiaries which are considered to be indefinitely reinvested, it is not practicable to calculate the exact unrecognized deferred tax liability, however it is not expected to be material as Ireland allows a tax credit in respect of distributions from foreign subsidiaries at the statutory tax rate in the jurisdiction of the subsidiary so that no material tax liability would be expected to arise in Ireland in the event these earnings were ever remitted. In addition, withholding taxes applicable to remittances from foreign subsidiaries would not be expected to be material given Ireland’s tax treaty network and the EU parent subsidiary directive.

A reconciliation of the beginning and ending amount of total unrecognized tax benefits is as follows:


	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Unrecognized tax benefits at start of year	$	19,078	$	20,156	$	21,433
Increase related to acquired tax positions	170,047		—		—
Increase related to prior year tax positions	204		401		—
Decrease related to prior year tax positions	(1,695)		(1,271)		—
Increase related to current year tax positions	18,613		2,931		1,588
Settlements	(844)		(369)		(347)
Lapse of statute of limitations	(3,338)		(2,770)		(2,518)
Unrecognized tax benefits at end of year	$	202,065	$	19,078	$	20,156

The relevant statute of limitations for unrecognized tax benefits totaling $38.8 million could potentially expire during 2022.

Included in the balance of total unrecognized tax benefits at December 31, 2021 were potential benefits of $202.1 million, which if recognized, would affect the effective rate on income tax from continuing operations. The balance of total unrecognized tax benefits at December 31, 2020 and December 31, 2019 included potential benefits which, if recognized, would affect the effective rate of income tax from continuing operations of $19.1 million and $20.2 million respectively.

Interest and penalties recognized during the year ended December 31, 2021 amounted to a net charge of $1.9 million (2020: ($0.6 million), 2019: Nil) and are included within the income tax expense. Total accrued interest and penalties as of December 31, 2021 and December 31, 2020 were $15.5 million and $0.5 million respectively and are included in closing income taxes payable at those dates.

Our major tax jurisdictions are Ireland and the United States. We may potentially be subjected to tax audits in both our major jurisdictions. In Ireland, tax periods open to audit include the years ended December 31, 2017, December 31, 2018, December 31, 2019, December 31, 2020 and December 31, 2021. In the United States, tax periods open to audit include the years ended December 31, 2016, December 31, 2017, December 31, 2018, December 31, 2019, December 31, 2020 and December 31, 2021. During such audits, local tax authorities may challenge the positions taken by us in our tax returns.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

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-Topic 740
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Restructuring charges

12 Months Ended

Dec. 31, 2021

Restructuring and Related Activities [Abstract]

Restructuring charges

A restructuring charge of $31.1 million was recognized during the year ended December 31, 2021 under a restructuring plan adopted following a review of operations. The restructuring plan reflected resource rationalization across the business to improve employee utilization and an office consolidation program to optimize the Company's office footprint. The restructuring plan resulted in a charge of $4.8 million relating to workforce reductions, an impairment of ROU assets and associated unavoidable costs totaling $21.9 million and fixed asset impairment of $4.4 million.


	Year Ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Restructuring charges	$	31,105	$	18,089	$	—
Net charge	$	31,105	$	18,089	$	—

At December 31, 2021, a total liability of $28.4 million was on the Consolidated Balance Sheet relating to restructuring activities. The total liability included $23.2 million from lease and lease related liabilities of which $10.4 million is included within other liabilities and $12.8 million is included within non-current operating lease liabilities. The remaining provision of $5.2 million relates to workforce reduction and is included within other liabilities.


	Year Ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)

Opening provision	$	10,748	$	1,637	$	6,419
Additional provision in the year	26,674		18,089		—
Utilization	(9,069)		(8,978)		(4,782)
Ending provision	$	28,353	$	10,748	$	1,637

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation We do not expect any litigation to have a materially adverse effect on our financial condition or results of operations. However, from time to time, we may become involved in various lawsuits and legal proceedings which arise in the ordinary course of business. Litigation is subject to inherent uncertainties, and an adverse result in these or other matters may arise from time to time that may harm our business. Operating Leases The Company has several non-cancelable operating leases, primarily for facilities, that expire over the next twelve years. These leases generally contain renewal options and require the Company to pay all executory costs such as maintenance and insurance. See note 23 - Operating leases for rental expense pursuant to ASC 842 for the years ended December 31, 2021 and December 31, 2020 and future minimum rental commitments as of December 31, 2021.

Disaggregation of Revenue

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

Revenue disaggregated by customer profile is as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Top client	$	441,173	$	337,904	$	350,287
Clients 2-5	1,291,946		754,906		704,963
Clients 6-10	752,325		350,865		347,832
Clients 11-25	1,077,073		501,643		529,713
Other	1,918,309		851,970		873,044
Total	$5,480,826		$2,797,288		$2,805,839

Our customers have similar profiles and economic characteristics, and therefore have similar degrees of risk and growth opportunities.Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities)

Accounts receivable and unbilled revenue are as follows:


	December 31, 2021		December 31, 2020
	(in thousands)
Billed services (accounts receivable)	$	1,349,851	$	722,420
Allowance for credit losses (note 19)	(7,081)		(7,149)
Accounts receivable (net)	1,342,770		715,271
Unbilled services (unbilled revenue)	$	623,121	$	428,684
Accounts receivable and unbilled revenue, net	$	1,965,891	$	1,143,955

Unbilled services and unearned revenue or payments on account (contract assets and liabilities) were as follows:


(in thousands, except percentages)	December 31, 2021		December 31, 2020		$ Change		% Change

Unbilled services (unbilled revenue)	$	623,121	$	428,684	$	194,437	45.4	%
Unearned revenue (payments on account)	(1,323,961)		(660,883)		(663,078)		100.3	%
Net balance	$	(700,840)	$	(232,199)	$	(468,641)	(201.8)	%

Timing may differ between the satisfaction of performance obligations and the invoicing and collection of amounts related to our contracts with customers. We record assets for amounts related to performance obligations that are satisfied but not yet billed and/or collected. These assets are recorded as unbilled revenue and therefore contract assets rather than accounts receivables when receipt of the consideration is conditional on something other than the passage of time. Liabilities are recorded for amounts that are collected in advance of the satisfaction of performance obligations or billed in advance of the revenue being earned.

Unbilled services/revenue balances arise where invoicing or billing is based on the timing of agreed milestones related to service contracts for clinical research. Contractual billing arrangements in respect of certain reimbursable expenses (principally investigators) require billing by the investigator to the Company prior to billing by the Company to the customer. As there is no contractual right of set-off between unbilled services (contract assets) and unearned revenue (contract liabilities), each are separately presented gross on the Consolidated Balance Sheet.

The Company is the contract principal in respect of both direct services and in the use of third parties (principally investigator services) that support a clinical trial. The progress towards completion for clinical service contracts is measured based on total project costs (including reimbursable costs). Amounts owed to investigators and others in respect of reimbursable expenses at December 31, 2021 and December 31, 2020 were $323.6 million and $138.2 million (see note 8 - Other liabilities).

Unbilled services as at December 31, 2021 increased by $194.4 million as compared to December 31, 2020. Unearned revenue increased by $663.1 million over the same period resulting in a increase of $468.6 million in the net balance of unbilled services and unearned revenue or payments on account between December 31, 2020 and December 31, 2021. These fluctuations are primarily due to the completion of the Merger on July 1, 2021 but are also partially due to timing of payments and invoicing related to the Group's clinical trial management contracts. Billings and payments are established by contractual provisions including predetermined payment schedules which may or may not correspond to the timing of the transfer of control of the Company's services under the contract. Unbilled services arise from long-term contract when a cost-based input method of revenue recognition is applied and revenue recognized exceeds the amount billed to the customer.

The credit loss expense recognized on the Group's receivables and unbilled services was $0.9 million and $2.9 million for the twelve months ended December 31, 2021 and 2020, respectively.

As of December 31, 2021 approximately $13.3 billion of revenue is expected to be recognized in the future in respect of unsatisfied performance obligations. The Company expects to recognize revenue on approximately 48% of the unrealized performance obligation over the next twelve months, with the remainder recognized thereafter over the duration of the customer contracts.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (b)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 12
-Subparagraph (e)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Topic 606
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

+ Details

Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities)

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities)

Disaggregation of Revenue

Revenue disaggregated by customer profile is as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Top client	$	441,173	$	337,904	$	350,287
Clients 2-5	1,291,946		754,906		704,963
Clients 6-10	752,325		350,865		347,832
Clients 11-25	1,077,073		501,643		529,713
Other	1,918,309		851,970		873,044
Total	$5,480,826		$2,797,288		$2,805,839

Accounts receivable and unbilled revenue are as follows:


	December 31, 2021		December 31, 2020
	(in thousands)
Billed services (accounts receivable)	$	1,349,851	$	722,420
Allowance for credit losses (note 19)	(7,081)		(7,149)
Accounts receivable (net)	1,342,770		715,271
Unbilled services (unbilled revenue)	$	623,121	$	428,684
Accounts receivable and unbilled revenue, net	$	1,965,891	$	1,143,955

Unbilled services and unearned revenue or payments on account (contract assets and liabilities) were as follows:


(in thousands, except percentages)	December 31, 2021		December 31, 2020		$ Change		% Change

Unbilled services (unbilled revenue)	$	623,121	$	428,684	$	194,437	45.4	%
Unearned revenue (payments on account)	(1,323,961)		(660,883)		(663,078)		100.3	%
Net balance	$	(700,840)	$	(232,199)	$	(468,641)	(201.8)	%

The credit loss expense recognized on the Group's receivables and unbilled services was $0.9 million and $2.9 million for the twelve months ended December 31, 2021 and 2020, respectively.

- Definition

+ References

+ Details

Provision for Credit Losses

12 Months Ended

Dec. 31, 2021

Accounts Receivable, after Allowance for Credit Loss [Abstract]

Provision for Credit Losses

The Company does business with most major international pharmaceutical companies. Provision for credit losses at December 31, 2021 and December 31, 2020 comprises:


	December 31, 2021		December 31, 2020
	(in thousands)
Opening provision	$	7,149	$	7,380
Amounts used during the year	(116)		(2,561)
Amounts provided during the year	705		2,692
Amounts released during the year	(544)		(510)
Foreign exchange	(113)		148
Closing provision	$	7,081	$	7,149

Business Segment and Geographical Information

12 Months Ended

Dec. 31, 2021

Segment Reporting [Abstract]

Business Segment and Geographical Information

The Company is a clinical research organization ("CRO"), providing outsourced development services on a global basis to the pharmaceutical, biotechnology and medical device industries. It specializes in the strategic development, management and analysis of programs that support all stages of the clinical development process - from compound selection to Phase I-IV clinical studies. The Company has the expertise and capability to conduct clinical trials in most major therapeutic areas on a global basis and has the operational flexibility to provide development services on a stand-alone basis or as part of an integrated "full-service" solution. The Company has expanded through internal growth, together with a number of strategic acquisitions to enhance its expertise and capabilities in certain areas of the clinical development process.

The Company determines and presents operating segments based on the information that is internally provided to the chief operating decision maker, the (‘CODM’) in accordance with ASC 280 'Segment Reporting'. The Company determined that the CODM was comprised of the Chief Executive Officer and the Chief Financial Officer.

The Company operates as one business segment, which is the provision of outsourced development services on a global basis to the pharmaceutical, biotechnology and medical devices industries.

Revenues are allocated to individual entities based on where the work is performed in accordance with the Company's global transfer pricing model. Revenues and income from operations in Ireland are a function of our global contracting model and the Group’s transfer pricing model.

ICON Ireland (Ireland Segment) acts as the Group entrepreneur under the Company’s global transfer pricing model given its role in the development and management of the Group, its ownership of key intellectual property and customer relationships, its key role in the mitigation of risks faced by the Group and its responsibility for maintaining the Company’s global network. ICON Ireland enters into the majority of the Company’s customer contracts.

ICON Ireland remunerates other operating entities in the ICON Group on the basis of a guaranteed cost plus mark-up for the services they perform in each of their local territories. The cost plus mark-up for each ICON entity is established to ensure that each of ICON Ireland and the ICON entities that are involved in the conduct of services for customers, earn an appropriate arms-length return having regard to the assets owned, risks borne, and functions performed by each entity from these intercompany transactions. The cost plus mark-up policy is reviewed annually to ensure that it is market appropriate. The integration of entities acquired through the Merger into this global network and global transfer pricing model remains ongoing.

The geographic split of revenue disclosed for each region outside Ireland is the cost plus revenue attributable to these entities. The residual revenues of the Group, once each ICON entity has been paid its respective intercompany service fee, generally fall to be retained by ICON Ireland. As such, revenues and income from operations in Ireland are a function of this global transfer pricing model and comprise revenues of the Group after deducting the cost plus revenues attributable to the activities performed outside Ireland. The integration of entities acquired through the Merger into the global transfer pricing model remains ongoing and these entities were not substantially part of the Group's cost plus arrangement in the year ended December 31, 2021.

The Company's areas of operation outside of Ireland include the United States, United Kingdom, Austria, Belgium, Bulgaria, Czech Republic, France, Germany, Hungary, Italy, Latvia, Poland, Portugal, Romania, Russia, Serbia, Spain, Sweden, The Netherlands, Turkey, Ukraine, Canada, Argentina, Brazil, Chile, Colombia, Mexico, Peru, China (including Hong Kong), India, Israel, Japan, Singapore, South Korea, The Philippines, Taiwan, Thailand, Australia, New Zealand, South Africa, Belarus, Bermuda, British Virgin Islands, Costa Rica, Croatia, Denmark, Egypt, Estonia, Finland, Georgia, Greece, Guatemala, Iceland, Jersey, Kenya, Lithuania, Luxembourg, Malaysia, Norway, Panama, Puerto Rico, Slovakia, Switzerland and Uruguay.

There have been no changes to the basis of segmentation or the measurement basis for the segment results since the prior year.

Reportable segment and geographic information at December 31, 2021 and December 31, 2020 and for the years ended December 31, 2021, December 31, 2020 and December 31, 2019 is as follows:

a) The distribution of revenue by geographical area was as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019

	(in thousands)
Ireland	$	1,365,909	$	1,181,292	$	1,252,834
Rest of Europe	1,175,515		416,884		388,916
U.S.	2,581,007		925,563		892,497
Other	358,395		273,549		271,592
Total	$	5,480,826	$	2,797,288	$	2,805,839

b) The distribution of income from operations, excluding restructuring, transaction and integration related expenses, by geographical area was as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Ireland *	$	161,862	$	295,360	$	314,287
Rest of Europe	183,436		35,402		37,997
U.S.	231,971		56,921		60,272
Other	30,628		21,147		20,850
Total	$	607,897	$	408,830	$	433,406

* Includes the full amount of the amortization charge associated with the intangible asset acquired in the Merger. These assets have been provisionally allocated to Ireland.

Income from operations, excluding restructuring, transaction and integration related expenses of $607.9 million was earned during the year ended December 31, 2021 having added back restructuring expenses of $31.1 million (see note 15 Restructuring charges) and transaction and integration related expenses of $198.3 million (see note 6 Business Combinations) to income from operations of $378.5 million as presented in the Consolidated Statement of Operations.

c) The distribution of long-lived assets (property, plant and equipment and operating right-of-use assets), net, by geographical area was as follows:


	December 31, 2021		December 31, 2020
	(in thousands)
Ireland	$	118,253	$	118,361
Rest of Europe	121,174		36,723
U.S.	239,828		65,152
Other	55,312		38,668
Total	$	534,567	$	258,904

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8924-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 32
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-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 280
-URI http://asc.fasb.org/topic&trid=2134510

+ Details

Supplemental Disclosure of Cash Flow Information

12 Months Ended

Dec. 31, 2021

Supplemental Cash Flow Elements [Abstract]

Supplemental Disclosure of Cash Flow Information


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Cash paid for interest	$	106,205	$	13,062	$	13,059
Cash paid for income taxes (net of refunds)	$	55,105	$	27,604	$	29,836

Accumulated Other Comprehensive Income

12 Months Ended

Dec. 31, 2021

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Accumulated Other Comprehensive Income


	Year ended
	December 31, 2021		December 31, 2020
	(in thousands)
Currency translation adjustments	$	(75,986)	$	(15,894)
Currency impact on long term funding	(9,854)		(9,329)
Actuarial loss on defined benefit pension plan (note 10)	(5,098)		(9,364)

Realized gain on interest rate hedge	—		4,658
Amortization of gain on interest rate hedge	—		(4,658)
Loss on interest rate hedge	—		(905)

Amortization of loss on interest rate hedge	1		15
Total	$	(90,937)	$	(35,477)

Operating Leases

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Operating Leases

Operating leases

Lease costs recorded under operating leases were as follows:


	Year ended
	December 31, 2021		December 31, 2020
	(in thousands)

Operating lease costs	$	51,200	$	31,088
Income from sub-leases	(1,338)		(940)
Net operating lease costs	$	49,862	$	30,148

Of the total cost of $49.9 million incurred in the year ended December 31, 2021, $47.5 million is recorded within selling, general and administration costs and $2.4 million is recorded within direct costs. Of the total cost of $30.1 million incurred in the year ended December 31, 2020, $27.6 million is recorded within selling, general and administration costs and $2.5 million is recorded within direct costs.

During the years ended December 31, 2021 and December 31, 2020, the Group did not incur any costs related to variable lease payments.

Right-of-use assets obtained, in exchange for lease obligations, net of early termination options now reasonably certain to be exercised, during the years ended December 31, 2021 and December 31, 2020 totaled $10.2 million and $12.1 million, respectively. During the year ended December 31, 2021, office consolidations resulted in the recognition of an impairment of ROU assets. The right-of-use assets related to these offices have been impaired and a charge of $15.4 million was recorded (see note 15 - Restructuring charges). An impairment charge of $5.4 million was recognized during the year ended December 31, 2020.

The weighted average remaining lease term and weighted-average discount rate at December 31, 2021 were 6.91 years and 2.51%, respectively. The weighted average remaining lease term and weighted-average discount rate at December 31, 2020 were 4.45 years and 2.53%, respectively.

Future minimum lease payments under non-cancelable leases as of December 31, 2021 were as follows:


	Minimum rental
	payments
	(in thousands)
2022	$	54,292
2023	45,469
2024	29,607
2025	20,758
2026	17,714
Thereafter	59,858
Total future minimum lease payments	227,698
Lease imputed interest	(18,266)
Total	$	209,432

Operating lease liabilities are presented as current and non-current. Operating lease liabilities of $49.9 million and $24.3 million have been included in other liabilities as at December 31, 2021 and December 31, 2020, respectively.

Non-current bank credit lines and loan facilities

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Non-current bank credit lines and loan facilities

The Company had the following debt outstanding as of December 31, 2021 and December 31, 2020:


			Principal amount
	Interest rate as of		December 31,		December 31,
(in thousands)	December 31, 2021		2021		2020		Maturity Date
Senior Secured Credit Facility
Term loan	2.75	%	$	5,001,213	$	—	July 2028

Senior Secured Notes	2.875	%	500,000		—		July 2026
2020 Senior Notes:
Series A notes			—		275,000
Series B notes			—		75,000
Total debt			5,501,213		350,000

Less current portion of long-term debt			(55,150)		—
Total long-term debt			5,446,063		350,000
Less debt issuance costs and debt discount			(64,901)		(1,523)
Total long-term debt, net			$	5,381,162	$	348,477

The Company paid a $27.6 million debt discount in connection with the Senior Secured Credit Facility and Senior Secured Notes.

The Company incurred interest costs from various financing arrangements during the years ended December 31, 2021, December 31, 2020 and December 31, 2019 as set out in the table below. These costs have been charged in the interest expense line of the Consolidated Statement of Operations. In the year ended December 31, 2021, the Company incurred $86.7 million transaction related financing costs (inclusive of the amortization of financing fees which were previously capitalized) associated with the debt facilities used to finance the Merger.


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)

Interest expense on drawn facilities	$	93,809	$	13,406	$	13,659
Amortization of financing costs	12,890		523		540
Transaction and one time financing costs	75,391		—		—
Other financing costs/(credits)	333		(910)		(923)
Total financing costs	$	182,423	$	13,019	$	13,276

As of December 31, 2021, the contractual maturities of the Company's debt obligations were as follows:


Current maturities of long-term debt:	(in thousands)
2022	55,150
2023	55,150
2024	55,150
2025	55,150
2026 and thereafter	5,280,613
Total	$	5,501,213

The Company's primary financing arrangements are its senior secured credit facilities (the "Senior Secured Credit Facilities"), which consists of a senior secured term loan and a revolving credit facility, and the senior secured notes (the "Senior Secured Notes").

Senior Secured Credit Facilities

In conjunction with the completion of the Merger Agreement, on July 1, 2021, ICON entered into a credit agreement providing for a senior secured term loan facility of $5,515 million and a senior secured revolving loan facility in an initial aggregate principal amount of $300 million. The proceeds of the senior secured term loan facility were used to repay in full (i) PRA’s existing credit facilities and (ii) the Company's private placement notes outstanding and fund, in part, the transaction. The senior secured term loan facility will mature in July 2028 and the revolving loan facility will mature in July 2026.

Borrowings under the senior secured term loan facility amortize in equal quarterly installments in an amount equal to 1.00% per annum of the principal amount, with the remaining balance due at final maturity. The interest rate margin applicable to borrowings under the senior secured term loan facility is LIBOR plus an applicable margin of 2.50%, in each case, with a step down of 0.25% if the first lien net leverage ratio is equal to or less than 4.00 to 1.00. The senior secured term loan facility is subject to a LIBOR floor of 0.50%. On November 10, 2021, the Company achieved a net leverage ratio of less than 4 times and the margin applicable to the senior secured term loan was reduced by 0.25% with the overall rate reducing from 3.0% to 2.75%.

The interest rate margin applicable to borrowings under the revolving loan facility will be, at the option of the borrower, either (i) the applicable base rate plus an applicable margin of 1.00%, 0.60% or 0.25% based on ICON’s current corporate family rating assigned by S&P of BB- (or lower), BB or BB+ (or higher), respectively, or (ii) LIBOR (or an alternative reference rate) plus an applicable margin of 2.00%, 1.60% or 1.25% based on ICON’s current corporate family rating assigned by S&P of BB- (or lower), BB or BB+ (or higher), respectively. In addition, lenders of under the revolving loan facility are entitled to commitment fees as a percentage of the applicable margin at the time of drawing and utilization fees dependent on the proportion of the facility drawn. At December 31, 2021, no amounts have been drawn under the revolving loan facility with the exception of $4.1 million letters of credit given to landlords to guarantee lease arrangements.

We continue to monitor the phasing out of LIBOR. We have engaged with our lenders on the implications of the change and will continue to discuss with them as replacement rates for LIBOR become more prevalent in the syndicated lending market. The Company is therefore subject to interest rate volatility in respect of the senior secured term loan facility, any future draw down on the Revolving Credit Facility or in respect of any future issuances of debt.

The Borrowers’ (as defined in the credit agreement) obligations under the Senior Secured Credit Facilities are guaranteed by ICON and the subsidiary guarantors. The Senior Secured Credit Facilities are secured by a lien on substantially all of ICON’s, the Borrowers’ and each of the subsidiary guarantor’s assets (subject to certain exceptions), and the Senior Secured Credit Facilities will have a first-priority lien on such assets, which will rank pari passu with the lien securing the Senior Secured Notes (see below), subject to other permitted liens. Our long-term debt arrangements contain customary restrictive covenants and, as of December 31, 2021, we were in compliance with our restrictive covenants in all material respects.

On September 27, 2021, the Company repaid $13.8 million of the senior secured term loan facility and made a quarterly interest payment of $40.4 million. On December 29, 2021, the Company repaid $500.0 million of the senior secured term loan facility and made a quarterly interest payment of $40.8 million. These repayments resulted in an additional charge associated with previously capitalized fees of $5.6 million. The Company is permitted to make prepayments on the senior secured term loan without penalty.

Senior Secured Notes

In addition to the Senior Secured Credit Facilities, on July 1, 2021, a subsidiary of the Company issued $500 million in aggregate principal amount of 2.875% senior secured notes due 2026 in a private offering (the “Offering”). The Senior Secured Notes will mature on July 15, 2026. The proceeds from the Offering and borrowings made under the Senior Secured Credit Facilities, together with cash on hand, were used to (i) fund the cash consideration payable by ICON for the Merger, (ii) repay existing indebtedness of ICON and PRA and (iii) pay fees and expenses related to the Merger, the Offering and the Senior Secured Credit Facilities. The Senior Secured Notes are guaranteed on a senior secured basis by ICON and its direct and indirect subsidiaries that guarantee the Senior Secured Credit Facilities.

2020 Senior Notes

On December 8, 2020, the Company issued new senior notes, (the "2020 Senior Notes") for aggregate gross proceeds of $350.0 million in the private placement market. The 2020 Senior Notes were issued in two tranches; Series A Notes of $275.0 million at a fixed interest rate of 2.32% and Series B Notes of $75.0 million at a fixed interest rate of 2.43%. The effective interest rate was adjusted by the impact of an interest rate cash flow hedge which was entered into in advance of the rate fixing date. This cash flow hedge was deemed to be fully effective in accordance with ASC 815 'Derivatives and Hedging'. The realized loss related to this derivative was recorded within other comprehensive income and amortized over the life of the 2020 Senior Notes. The effective rate on the 2020 Senior Notes was fixed at 2.41%.

In connection with the Merger, the Company was required to repay the 2020 Senior Notes prior to entering into the Senior Secured Credit Facilities and the Senior Secured Notes. In June 2021, ICON committed to entering into the Senior Secured Credit Facilities and the Senior Secured Notes and therefore committed to replacing the 2020 Senior Notes. The 2020 Senior Notes have been repaid and long term financing consisting of the Senior Secured Credit Facilities and the Senior Secured Notes have been drawn. The 2020 Senior Notes were repaid on July 1, 2021 inclusive of early repayment charges. The total repayment on July 1, 2021 was $364.0 million.

Fair Value of Debt

The estimated fair value of the Company’s debt was $5,507.2 million at December 31, 2021. The fair values of the Senior Secured Credit Facilities and Senior Secured Notes were determined based on Level 2 inputs, which are based on rates at which the debt is traded among financial institutions.

Fair Value	12 Months Ended
Fair Value	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value	Fair Value The Company records certain assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset, or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy that prioritizes the inputs used to measure fair value is described below. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: •Level 1 — Quoted prices in active markets for identical assets or liabilities. •Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. •Level 3 — Unobservable inputs that are supported by little or no market activity. This includes certain pricing models, discounted cash flow methodologies, and similar techniques that use significant unobservable inputs. The carrying amounts of financial instruments, including cash and cash equivalents, accounts receivable, unbilled services, contract assets, accounts payable, and unearned revenue approximate fair value due to the short maturities of these instruments. Recurring Fair Value Measurements The Company classifies its interests in investments in equity-long term having considered the nature of its investment, the extent of influence over operating and financial decisions and the availability of readily determinable fair values. The Company determined that the interests in funds at December 31, 2021 and December 31, 2020 meet the definition of equity securities without readily determinable fair values. The Company concluded that the interests held at December 31, 2021 and December 31, 2020 qualify for the Net Asset Value (NAV) practical expedient in ASC 820 'Fair value measurements and disclosures'. Any increases or decreases in fair value are recognized in net income in the period. These are therefore measured at Level 3 of the fair value hierarchy. There was an increase in fair value of $3.2 million (December 31, 2020: $2.5 million) recognized in net income during the year bringing the carrying value of the subscriptions to $22.6 million at December 31, 2021 (December 31, 2020: $15.8 million). Non-recurring Fair Value Measurements Certain assets and liabilities are carried on the accompanying Consolidated Balance Sheet at cost and are not re-measured to fair value on a recurring basis. These assets include finite-lived intangible assets that are tested for impairment when a triggering event occurs and goodwill that is tested for impairment annually or when a triggering event occurs. As of December 31, 2021, assets carried on the balance sheet and not re-measured to fair value on a recurring basis totaled approximately $13,748.8 million and are identified as Level 3 assets. These assets are comprised of goodwill of $9,037.9 million and identifiable intangible assets, net of $4,710.8 million. Refer to note 24 - Non-current bank credit lines and loan facilities for additional information regarding the fair value of long-term debt balances.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Impact of New Accounting Pronouncements	12 Months Ended
Impact of New Accounting Pronouncements	Dec. 31, 2021
Accounting Changes and Error Corrections [Abstract]
Impact of New Accounting Pronouncements	Impact of New Accounting Pronouncements Impact of new accounting pronouncements adopted during fiscal year ended December 31, 2021 (or previously) Business combinations In October 2021, the FASB issued ASU 2021-08 'Business Combinations (Topic 805) - Accounting for Contract Assets and Contract Liabilities from Contracts with Customers'. The amendments in this ASU require that an entity (acquirer) recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with Topic 606. At the acquisition date, an acquirer should account for the related revenue contracts in accordance with Topic 606 as if it had originated the contracts. For public business entities, the amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption of the amendments is permitted, including adoption in an interim period. An entity that early adopts in an interim period should apply the amendments (1) retrospectively to all business combinations for which the acquisition date occurs on or after the beginning of the fiscal year that includes the interim period of early application and (2) prospectively to all business combinations that occur on or after the date of initial application. The Company has taken the option to early adopt the amendments in this ASU for year ended December 31, 2021 and apply the amendments to interim periods from the beginning of the fiscal year. The Company has applied the amendments of this ASU to the Merger with PRA, completed on July 1, 2021. The application of these amendments has resulted in a $16.0 million increase in goodwill and corresponding $16.0 million increase to unearned revenue compared to the Company's Balance Sheet at September 30, 2021. Since July 1, 2021, the Company had amortized $4.0 million of the unearned revenue adjustment through the revenue line in the Consolidated Statement of Comprehensive Income. This amortization has been reversed in December 2021 resulting in a net nil impact on revenue for the year ended December 31, 2021. Other accounting pronouncements adopted during fiscal year ended December 31, 2021 In December 2019, the FASB issued ASU 2019-12 'Simplifying the Accounting for Income Taxes (Topic 740)'. The amendments in this update simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The Company adopted the amendments in this ASU on a prospective basis, except where the required method of adoption is retrospective or modified retrospective. ASU 2019-12 is effective for the Company for the year ended December 31, 2021. The adoption of this ASU did not have a significant impact on the financial statements. In January 2020, the FASB issued ASU 2020-01, 'Investments-Equity Securities (Topic 321), Investments-Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815)'. ASU 2020-01 states any equity security transitioning from the alternative method of accounting under Topic 321 to the equity method, or vice versa, due to an observable transaction will be re-measured immediately before the transition. In addition, the ASU clarifies the accounting for certain non-derivative forward contracts or purchased call options to acquire equity securities stating such instruments will be measured using the fair value principles of Topic 321 before settlement or exercise. The ASU is effective for the Company for the year ended December 31, 2021, and has been applied on a prospective basis. The adoption of this ASU did not have a significant impact on the financial statements. In August 2020, the FASB issued ASU 2020-06 ‘Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity’ which removes the separation models in ASC 470 ‘Debt’ for convertible debt with cash conversion features and convertible instruments with beneficial conversion features. The ASU also removes from ASC 815 ‘Derivatives and Hedge Accounting’ certain conditions for equity classification for contracts on an entity’s own equity. The ASU is effective for the Company for the year ended December 31, 2021. The adoption of this ASU did not have a significant impact on the financial statements. Impact of new accounting pronouncements which will be adopted during fiscal year ended December 31, 2022 No other new accounting pronouncement issued or effective has had, or is expected to have, a significant impact on the Company’s consolidated financial statements.

Related Parties	12 Months Ended
Related Parties	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Parties	Related Parties Subsidiaries of the Company earned revenue of $30,000 (December 31, 2020: $321,000) from DS Biopharma Limited (formerly Dignity Sciences Limited) during the year. Dr. John Climax is Executive Chairman and a Director and shareholder of DS Biopharma Limited. $12,000 was recorded as due from DS Biopharma Limited at December 31, 2021 (December 31, 2020: $41,000). Subsidiaries of the Company earned revenue of $551,000 (December 31, 2020: $9,000) from Afimmune Limited during the year. Dr. John Climax is Chief Executive Officer and a Director and shareholder of Afimmune Limited. $197,000 was recorded as due from Afimmune Limited at December 31, 2021 (December 31, 2020: $nil). On July 24, 2020, a subsidiary of the Company, ICON Clinical Research Limited, entered into an agreement to jointly establish a new company, Oncacare, with a third party. The Company has invested $4.9 million to obtain a 49% interest in the voting share capital of Oncacare. The Company provided corporate support services to Oncacare to the value of $465,000 during the year ended December 31, 2021. $264,000 was recorded as due from Oncacare at December 31, 2021. During the year ended December 31, 2021, the Company provided a loan of $10 million to Oncacare in order to fund the continued start up of the business' operations. The loan accrues annual interest at 1.6% and the loan is repayable on June 30, 2025. The full amount of this loan remains outstanding at December 31, 2021 along with accrued interest of $23,000. The majority investor in Oncacare has the right to sell the 51% majority voting share capital exclusively to the Company in an eighteen month period, commencing January 1, 2023 and ICON also has the right to acquire the 51% majority voting share capital from August 1, 2025.

Net Income Per Ordinary Share

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Net income per ordinary share

Basic net income per ordinary share attributable to the Group has been computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding during the period.

Diluted net income per ordinary share is computed by adjusting the weighted average number of ordinary shares outstanding during the period for all potentially dilutive ordinary shares outstanding during the period and adjusting net income for any changes in income or loss that would result from the conversion of such potential ordinary shares.

There is no difference in net income used for basic and diluted net income per ordinary share.

Basic and diluted net income per ordinary share attributable to the Group for the years ended December 31, 2020 and December 31, 2019 include the adjustment to reflect the accretion of the noncontrolling interest in MeDiNova to its redemption value. The noncontrolling interest was acquired in the year ended December 31, 2020 and therefore no adjustment has been required in the year ended December 31, 2021.

The reconciliation of the number of shares used in the computation of basic and diluted net income per ordinary share is as follows:


	December 31, 2021	December 31, 2020	December 31, 2019
Weighted average number of ordinary shares outstanding for basic net income per ordinary share	67,110,186	52,859,911	53,859,537
Effect of dilutive share options outstanding	958,125	423,674	473,924
Weighted average number of ordinary shares outstanding for diluted net income per ordinary share	68,068,311	53,283,585	54,333,461

The reconciliation between net income attributable to the Group per the Consolidated Statement of Operations and the net income used to calculate net income per ordinary share attributable to the Group is as follows:


	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Net income attributable to the Group	$	153,185	332,331		$	373,986
Noncontrolling interest adjustment to redemption amount	—		(4,522)		(5,048)
Net income attributable to the Group (including NCI redemption adjustment)	153,185		327,809		368,938

	December 31, 2021		December 31, 2020		December 31, 2019
Net income per Ordinary Share attributable to the Group (including NCI redemption adjustment):
Basic	$	2.28	$	6.20	$	6.85
Diluted	$	2.25	$	6.15	$	6.79

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated subsequent events from the Balance Sheet date through March 1, 2022, the date at which the consolidated financial statements were available to be issued. On February 18, 2022, the Company's Board of Directors authorized a new buyback program of up to $100 million of the outstanding ordinary shares of the Company. All ordinary shares that are redeemed under the buyback program will be canceled in accordance with the constitutional documents of the Company and the nominal value of these shares transferred to an undenominated capital fund as required under Irish Company law. Repurchases under the share buyback program may be effected from time to time in open market or privately negotiated transactions in accordance with agreed terms and limitations. The timing and amount of the repurchase transactions under this program will depend on a variety of factors, including market conditions and corporate and regulatory considerations. Depending upon results of operations, market conditions and the development of the economy, as well as other factors, generally we will consider share repurchases on an opportunistic basis from time to time. At March 1, 2022, the Company has repurchased $80.9 million of ordinary shares of the Company since December 31, 2021. The Company has determined that there are no other items to disclose.

Significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Basis of Consolidation

Basis of consolidationThe consolidated financial statements include the financial statements of the Company and all of its subsidiaries. All significant intercompany profits, transactions and account balances have been eliminated. The results of subsidiary undertakings acquired in the period are included in the Consolidated Statement of Operations from the date of acquisition.

Use of Estimates

Use of estimatesThe preparation of financial statements in conformity with generally accepted accounting principles in the United States requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates. The principal management estimates and judgments used in preparing the financial statements relate to revenue recognition and intangible assets acquired in a business combination.

Revenue Recognition

Revenue recognition

Clinical trial service revenue

Laboratory services revenue

Contracting services revenue

Consulting services revenue

Data services revenue

Commissions

Third Party Costs (Reimbursable expenses)

Pass-through/ Reimbursable expensesPass through/ Reimbursable expenses comprise investigator payments and certain other costs which are reimbursed by clients under terms specific to each contract to the investigators. See note 2 (e) Direct costs below.

(e) Direct costs

Direct costs consist of compensation, associated employee benefits and share-based payments for project-related employees and other direct project-related costs.

Advertising Costs

Advertising costsAll costs associated with advertising and promotion are expensed as incurred.

Foreign Currencies and Translation of Subsidiaries

Foreign currencies and translation of subsidiariesICON plc's financial statements are prepared in United States dollars. Transactions in currencies other than the functional currency of the individual entities within the ICON Group are recorded at the rate ruling at the date of the transaction. Monetary assets and liabilities denominated in currencies other than the functional currency of the individual entities within the ICON Group are translated into the functional currency of that entity at exchange rates prevailing at the Balance Sheet date. Adjustments resulting from these translations are charged or credited to income.The financial statements of subsidiaries with other functional currencies are translated at period end rates for the Consolidated Balance Sheets and average rates for the Consolidated Statements of Operations. Translation gains and losses arising are reported as a movement on accumulated other comprehensive income. Foreign currency transaction gains and losses are reported in other comprehensive income ("currency impact of long term funding") rather than through income where the foreign currency transaction is 'long-term investment' in nature i.e. settlement is not planned or anticipated in the foreseeable future.

Disclosure of Fair Value of Financial Instruments

Disclosure of fair value of financial instruments


Level 1:			Inputs are based upon unadjusted quoted prices for identical instruments traded in active markets.

Level 2:			Inputs are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3:			Inputs are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability.

Business Combinations

Business combinations

The Company allocates a share of net income to the noncontrolling interest holders based on percentage ownership.

Transaction and integration-related expensesTransaction and integration-related expenses are the incremental costs directly attributable to the completion and integration activities associated with the Company’s recent acquisitions. The costs consist of investment banking fees, advisory costs, retention agreements with employees, accelerated share compensation charges, contingent consideration valuation adjustments and ongoing integration activities. The Company accounts for these transaction and integration-related costs as expenses in the period in which the costs are incurred and the services are received.

Goodwill and Impairment

Goodwill and ImpairmentGoodwill represents the excess of the cost of acquired entities over the net amounts assigned to assets acquired and liabilities assumed. Goodwill primarily comprises acquired workforce in place which does not qualify for recognition as an asset apart from goodwill. Goodwill is stated net of any provision for impairment. The Company tests goodwill annually for any impairments or whenever events occur which may indicate impairment. An impairment charge would be recognized for any amount by which the carrying amount exceeds the reporting unit's fair value up to the amount of existing goodwill. The Company performs a qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary.

Intangible Assets

Intangible assetsIntangible assets are amortized on a straight line basis over their estimated useful life.

Cash and Cash Equivalents

Cash and cash equivalentsCash and cash equivalents include cash and highly liquid investments with initial maturities of three months or less and are stated at cost, which approximates market value.

Investment in Debt, Equity and Other

Investments in debt, equity and other

Available for sale investments

Long term investments

Equity method investments

Accounts Receivable, Net and Unbilled Revenue

Accounts receivable, net and unbilled revenue

Accounts receivable factoringWhere the Company enters into an agreement to sell certain portfolios of its accounts receivable balances, the sale is accounted for in accordance with ASC Topic 860 'Transfers and Servicing' (ASC 860). Agreements which result in true sales of the transferred receivables, as defined in ASC 860, which occur when receivables are transferred without recourse to ICON, are excluded from amounts reported in the Consolidated Balance Sheet. Cash proceeds received from such sales are included in operating cash flows. The associated finance costs are presented as interest expense.

Inventory

InventoryInventory is valued at the lower of cost and net realizable value and after provisions for obsolescence. The cost of inventories comprises the purchase price and attributable costs, less trade discounts.

Property, Plant and Equipment

Property, plant and equipment


			Years
Building			40
Computer equipment and software			2-8
Office furniture and fixtures			8
Laboratory equipment			5
Motor vehicles			5

Leasehold improvements are amortized using the straight line method over the estimated useful life of the asset or the lease term, whichever is shorter.

Leases

Income Taxes

Income taxesThe Company applies the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amount of existing assets and liabilities and their respective tax bases and for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which these temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are reduced by a valuation allowance to the amount that is more likely than not to be realized. The Company recognizes the effect of income tax positions only if those positions will more likely than not be sustained. Recognized income tax positions are measured at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon settlement. Interest and penalties related to income taxes are included in income tax expense and classified with the related liability on the Consolidated Balance Sheet. The Company accounts for the impact of GILTI (“global intangible low-taxed income”) in the period it arises and has therefore not provided for deferred taxes in respect of this item.

Government Grants

Government grants

Research and Development Credits

Research and development creditsResearch and development credits are available to the Company under the tax laws in certain jurisdictions, based on qualifying research and development spend as defined under those tax laws. Research and development credits are generally recognized as a reduction of income tax expense. However, certain tax jurisdictions provide refundable credits that are not wholly dependent on the Company's ongoing income tax status or income tax position. In these circumstances the benefit of these credits is not recorded as a reduction to income tax expense, but rather as a reduction of operating expenditure.

Pension Costs

Pension costs

Redeemable Non-Controlling Interests and Equity

Redeemable noncontrolling interests and equityThe Company acquired a majority ownership interest in MeDiNova during the year ended December 31, 2019. Included in the purchase agreement were put and call option arrangements with the noncontrolling interest holders that required (put option) or enabled (call option) the Company to purchase the remaining minority ownership at a future date. The option was accounted for as temporary equity, which is presented separately as redeemable noncontrolling interest on the Consolidated Balance Sheet. This classification reflects the assessment that the instruments are contingently redeemable in accordance with ASC 480-10-S99 'Distinguishing Liabilities from Equity'. On March 9, 2020, ICON exercised its option to call the remaining shares and took 100% ownership of MeDiNova. Redeemable noncontrolling interests are accreted to their redemption value over the period from the date of issuance to the first date on which the option is exercisable. The change in the option's redemption value is recorded against retained earnings. In a computation of earnings per share, the accretion of redeemable noncontrolling interests to their redemption value is a reduction of net income attributable to the Group. Basic and diluted net income per ordinary share attributable to the Group includes the adjustment to reflect the accretion of the noncontrolling interest to its redemption value until the redemption of the noncontrolling interest on March 9, 2020.

Net Income per Ordinary Share

Net income per ordinary shareBasic net income per ordinary share attributable to the Company has been computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding during the period. Diluted net income per ordinary share is computed by adjusting the weighted average number of ordinary shares outstanding during the period for all potentially dilutive ordinary shares outstanding during the period and adjusting net income for any changes in income or loss that would result from the conversion of such potential ordinary shares. There is no difference in net income used for basic and diluted net income per ordinary share. Basic and diluted net income per ordinary share attributable to the Company includes the adjustment to reflect the accretion of the noncontrolling interest in MeDiNova to its redemption value (see note 27 - Net income per ordinary share).

Share-Based Compensation

Share-based compensation

Liability classified awards are measured at the fair value of the award on the grant date and remeasured at each reporting period at fair value until the award is settled.

Replacement awards

Impairment of Long-Lived Assets

Impairment of long-lived assetsLong-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of the asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured at the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets to be disposed of are reported at the lower of the carrying amount of the asset or fair value less selling costs.

Derivative Financial Instruments

Derivative financial instruments

Debt Issuance Costs

Debt issuance costsDebt issuance costs relating to the Company’s long-term debt are recorded as a direct reduction of long-term debt; these costs are deferred and amortized to interest expense using the effective interest method, over the respective terms of the related debt. Debt issuance costs relating to the Company’s revolving credit facilities are recorded as an asset; these costs are deferred and amortized to interest expense using the straight-line method. Early repayment of debt facilities can result in modification of the debt and the acceleration of the amortization of debt issuance costs.

Transaction and Integration-related Expenses

Business combinations

The Company allocates a share of net income to the noncontrolling interest holders based on percentage ownership.

Restructuring

RestructuringRestructuring charges reflect certain one-time costs arising from reorganization programs announced by Company management. These programs generally result in asset impairments and workforce reductions in order to optimize the Company’s structure and facilitate improved long-term performance. Impairment charges are taken when the value-in-use of the asset is less than the asset’s carrying value. Workforce related charges are taken when an approved reorganization program is communicated to the relevant employee groups.

Reclassifications

ReclassificationsCertain prior period amounts in the consolidated financial statements and accompanying notes have been reclassified to conform to the current period’s presentation. Most notably, the Company has presented transaction and integration-related expenses as a separate line in the Consolidated Statement of Operations and reclassified certain costs incurred in the years ended December 31, 2020 and December 31, 2019 within this line. These costs consist of transaction and integration-related expenses and contingent consideration valuation adjustments related to ICON's prior period acquisitions. These costs were previously presented in the selling, general and administrative expenses but have been reclassified to transaction and integration-related expenses to conform to the current period’s presentation.

Significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Adjustments Resulting From Foreign Currency Translations

Amounts charged or credited to the Consolidated Statements of Operations for the years ended December 31, 2021, December 31, 2020 and December 31, 2019 were as follows:


	Year ended December 31,
	2021		2020		2019
	(in thousands)
Amounts (credited)/charged	$	(14,316)	$	5,979	$	590

Estimated Useful Lives of Assets

Depreciation of property, plant and equipment is computed using the straight line method based on the estimated useful lives of the assets as listed below:


			Years
Building			40
Computer equipment and software			2-8
Office furniture and fixtures			8
Laboratory equipment			5
Motor vehicles			5

Investments (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Cost and Fair Value of Investments


	December 31, 2021		December 31, 2020
	(in thousands)
Available for sale investments at start of year	$	1,729	$	49,628

Purchases	480		—
Sales and maturities	(497)		(47,902)

Realized gain on sale of short term investments	—		234
Unrealized capital loss – investments	—		(231)
Available for sale investments at end of year	$	1,712	$	1,729

Available For Sale Short Term Investments by Major Security Type

The following table represents our available for sale short term investments by major security type as of December 31, 2021:


					Maturity by period
	Cost Total		Fair Value Total		Less than 1 year		1 to 5 years
	(in millions)


Term deposits	$	1.7	$	1.7	$	0.5	$	1.2
Total ($ in millions)	$	1.7	$	1.7	$	0.5	$	1.2

Equity Method Investments

The following table represents our equity method investments at December 31, 2021:


	Ownership Percentage		Carrying Value		Carrying Value

	December 31, 2021		December 31, 2021		December 31, 2020
			(in thousands)
Oncacare Limited	49	%	$	2,373	$	4,534

Goodwill (Tables)

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill


	December 31, 2021		December 31, 2020
	(in thousands)
Opening goodwill	$	936,257	$	883,170
Current year acquisitions (note 6)	8,120,006		27,191
Prior period acquisition	—		123
Foreign exchange movement	(18,332)		25,773
Closing goodwill	$	9,037,931	$	936,257

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets


	December 31, 2021		December 31, 2020
Cost	(in thousands)
Customer relationships	$	4,056,642	$	144,251
Order backlog	528,022		39,269
Trade names & brands	204,685		2,766
Patient database	170,525		2,552
Technology assets	121,507		11,173
Total cost	5,081,381		200,011

Accumulated amortization	(370,538)		(133,551)
Net book value	$	4,710,843	$	66,460

Schedule of Future Intangible Asset Amortization Expense

Future intangible asset amortization expense for the years ended December 31, 2022 to December 31, 2026 is as follows:


	Year Ended December 31, 2021
	(in thousands)
2022	$	456,973
2023	454,235
2024	338,463
2025	222,191
2026	208,175
	$	1,680,037

Business combinations (Tables)

12 Months Ended

Dec. 31, 2021

Business Combinations [Abstract]

Schedule of Business Acquisitions, by Acquisition

The Merger Date fair value of the consideration transferred consisted of the following:


			(in thousands)
Fair value of cash consideration			5,308,646
Fair value of ordinary shares issued to acquiree stockholders			5,658,126
Fair value of replacement share-based awards issued to acquiree employees			209,399
Repayment of term loan obligations and accrued interest *			865,800
			12,041,971

* This represents the portion of PRA debt paid by ICON. PRA also paid $401.6 million from available cash to settle debt obligations that existed at the Merger Date.

Summary of Estimates of Fair Values of Assets Acquired and Liabilities Assumed


	July 1,
	2021
	(in thousands)
Cash and cash equivalents	$	259,971
Accounts receivable and unbilled revenue	934,308
Other current assets	125,156
Fixed assets	156,851
Operating lease right-of-use assets	177,345
Goodwill *	8,120,006
Intangible assets	4,886,000
Deferred tax assets	28,099
Other assets	35,391
Accounts payable	(50,259)
Accrued expenses and other current liabilities	(380,342)
Current portion of operating lease liabilities	(36,625)
Unearned revenue	(739,278)
Non-current portion of operating lease liabilities	(144,403)
Deferred tax liabilities	(1,126,952)
Other non-current liabilities	(203,297)

Net assets acquired	$	12,041,971

The following table summarizes the Company’s fair values of the assets acquired and liabilities assumed:


	January 22,
	2020
	(in thousands)
Cash & cash equivalents	$	10,170
Property, plant and equipment	45
Operating right of use assets	539
Goodwill *	27,191
Customer relationships	11,725
Order backlog	2,883
Accounts receivable	3,033


Prepayments and other current assets	158
Accounts payable	(368)
Unearned revenue	(989)
Other liabilities	(2,202)
Current lease liabilities	(219)
Non-current lease liabilities	(320)
Non-current deferred tax liability	(4,090)

Net assets acquired	$	47,556

Cash outflows	$	46,992
Working capital adjustment paid	564
Contingent consideration **	—

Total consideration	$	47,556

Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination


	Estimated Fair Value	Estimated Useful Life
Customer relationships	3,915,000	23 years
Order backlog	490,000	3 years
Trade names	202,000	3 years
Patient database	168,000	7 years
Technology assets	111,000	5 years
	4,886,000

Summary of Proforma Information per Acquisition

Consequently, actual future results of the Company will differ from the pro forma financial information presented below:


	Year Ended		Year ended
	December 31		December 31
	2021		2020
	(in thousands)
Revenue	$	7,462,000	$	5,980,653
Net income/(loss)	$	340,942	$	(149,658)

The proforma effect of the MedPass acquisition if completed on January 1, 2019 would have resulted in revenue and net income for the fiscal years ended December 31, 2020 and December 31, 2019 as follows:


	Year Ended
	2020		2019
	(in thousands)
Revenue	$	2,798,180	$	2,820,796
Net income	$	332,521	$	377,485

Property, Plant and Equipment, net (Tables)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Schedule of Property Plant and Equipment, Net


	December 31, 2021		December 31, 2020
	(in thousands)
Cost
Land	$	3,724	$	3,724
Building	82,017		90,139
Computer equipment and software	506,322		440,930
Office furniture and fixtures	107,507		91,933
Laboratory equipment	29,210		44,567
Leasehold improvements	70,123		32,261
Motor vehicles	65		160

	798,968		703,714
Less accumulated depreciation and asset write offs	(462,524)		(529,371)

Property, plant and equipment (net)	$	336,444	$	174,343

Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2021

Other Liabilities Disclosure [Abstract]

Schedule of Other Liabilities


	December 31, 2021		December 31, 2020
	(in thousands)
General trade and overhead liabilities*	$	459,814	$	188,638
Personnel related liabilities	413,185		161,363
Operating lease liabilities (note 23)	49,949		24,334
Facility related liabilities	12,055		9,441
Other liabilities	7,204		8,726
Restructuring liabilities (note 15)	7,377		7,219
Short term government grants	45		48
	$	949,629	$	399,769

*includes amounts due to third parties in respect of accrued reimbursable investigator expenses of $323.6 million at December 31, 2021 and $138.2 million at December 31, 2020.

Non-Current Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2021

Payables and Accruals [Abstract]

Non-Current Other Liabilities


	December 31, 2021		December 31, 2020
	(in thousands)
Defined benefit pension obligations, net (note 10)	$	16,262	$	10,395
Other non-current liabilities	25,599		15,971
	$	41,861	$	26,366

Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan


Funded status	December 31, 2021		December 31, 2020
	(in thousands)
Projected benefit obligation	$	(41,813)	$	(43,988)
Fair value of plan assets	36,198		34,612
Funded status	$	(5,615)	$	(9,376)
Non-current other liabilities (note 9)	$	(5,615)	$	(9,376)


Change in benefit obligation	December 31, 2021		December 31, 2020
	(in thousands)
Benefit obligation at beginning of year	$	43,988	$	37,036
Service cost	134		100
Interest cost	665		746
Plan participants' contributions	23		22

Benefits paid	(489)		(724)
Actuarial (gain)/loss	(2,097)		5,294
Foreign currency exchange rate changes	(411)		1,514
Benefit obligation at end of year	$	41,813	$	43,988


Change in plan assets	December 31, 2021		December 31, 2020
	(in thousands)
Fair value of plan assets at beginning of year	$	34,612	$	32,016
Actual return on plan assets	2,347		2,092
Employer contributions	91		109
Plan participants' contributions	23		22
Benefits paid	(489)		(724)
Foreign currency exchange rate changes	(386)		1,097
Fair value of plan assets at end of year	$	36,198	$	34,612


Funded status	December 31, 2021		December 31, 2020
	(in thousands)
Projected benefit obligation	$	(7,643)	$	(8,620)
Fair value of plan assets	6,964		7,601
Funded status	$	(679)	$	(1,019)
Non-current other liabilities (note 9)	$	(679)	$	(1,019)


Change in benefit obligation	December 31, 2021		December 31, 2020
	(in thousands)
Benefit obligation at beginning of year	$	8,620	$	7,047
Service cost	150		139
Interest cost	12		21
Plan participants' contributions	95		81
Settlement	(483)		—
Prior service cost	(82)		(23)
Transferred balances	76		245
Actuarial (gain)/ loss	(484)		406
Foreign currency exchange rate changes	(261)		704
Benefit obligation at end of year	$	7,643	$	8,620


Change in plan assets	December 31,		December 31,
	2021		2020
	(in thousands)
Fair value of plan assets at beginning of year	$	7,601	$	6,014
Expected return on plan assets	15		21
Actual return on plan assets	(238)		519
Scheme contributions	128		105
Plan participants' contributions	95		81
Transferred balances	76		245
Settlement	(483)		—
Foreign currency exchange rate changes	(230)		616
Fair value of plan assets at end of year	$	6,964	$	7,601

The pension costs of this plan are presented in the following tables in accordance with the requirements of ASC 715-60 'Defined Benefit Plans – Other Postretirement'.


Funded status	December 31, 2021
	(in thousands)
Projected benefit obligation	$	(4,990)
Fair value of plan assets	3,017
Funded status	$	(1,973)
Non-current other liabilities (note 9)	$	(1,973)


Change in benefit obligation	December 31, 2021
	(in thousands)
Benefit obligation as at July 1, 2021	$	4,890
Service cost	207
Interest cost	19
Plan participants’ contributions	135


Transferred benefits paid	(113)
Actuarial loss	1
Foreign currency exchange rate changes	(149)
Benefit obligation at end of year	$	4,990


Change in plan assets	December 31,
	2021
	(in thousands)
Fair value of plan assets at as at July 1, 2021	$	2,849
Expected return on plan assets	15

Scheme contributions	135
Plan participants’ contributions	135
Transferred benefits paid	(113)

Foreign currency exchange rate changes	(4)
Fair value of plan assets at end of year	$	3,017

Schedule of Components of Net Periodic Benefit Cost

The following amounts were recorded in the Consolidated Statement of Operations as components of the net periodic benefit cost:


	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Service cost	$	134	$	100	$	107
Interest cost	665		746		867
Expected return on plan assets	(1,171)		(1,214)		(574)
Amortization of net loss	625		160		67

Net periodic benefit cost	$	253	$	(208)	$	467

Summary of Assumptions Used in Calculating Pension Benefit Obligations


	December 31, 2021		December 31, 2020		December 31, 2019
Discount rate	1.5	%	2.1	%	2.9	%
Rate of compensation increase	3.4	%	3.3	%	3.7	%
Expected rate of return on plan assets	3.4	%	4.0	%	2.1	%

The following assumptions were used in determining the benefit obligation at December 31, 2021 and December 31, 2020:


	December 31, 2021		December 31, 2020
Discount rate	1.8	%	1.5	%
Rate of compensation increase	3.7	%	3.4	%

Schedule of Amounts Recognized in Other Comprehensive Income (Loss)


Other comprehensive income	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Actuarial (gain)/loss - benefit obligation	$	(2,097)	$	5,294	$	4,756
Actuarial gain – plan assets	(1,176)		(878)		(2,930)
Actuarial loss recognized in net periodic benefit cost	(625)		(160)		(67)
Total	$	(3,898)	$	4,256	$	1,759

Summary of Expected Long Term Rates of Return on Different Asset Classes

The expected long term rates of return on different asset classes are as follows:


Expected long-term return per annum	December 31, 2021		December 31, 2020
Corporate Bonds (including 50% high yield bonds)	2.8	%	2.8	%
Equities	5.5	%	5.2	%
Secured Loans and Multi Asset Credit	3.0	%	3.0	%

Schedule of Underlying Asset Split of Fund

The underlying asset split of the fund is shown below.


Asset Category	December 31, 2021		December 31, 2020
Corporate Bonds (including 50% high yield bonds)	37	%	40	%
Equities	24	%	21	%
Secured Loans and Multi Asset Credit	39	%	39	%


	100	%	100	%

Schedule of Plan Asset Fair Value Measurements


	Quoted Prices in Active Markets for Identical Assets Level 1
	December 31, 2021		December 31, 2020
	(in thousands)
Cash	$	162	$	11
Fixed Income Securities
L&G Life GPBF All World Equity Index Fund	8,743		7,460
L&G Life DC Active Corporate Bond	6,409		6,797
Stone Harbor High Yield Bond Fund	6,965		6,861
Ninety One Global Total Return Credit	3,435		3,472

Stone Harbor Multi Asset Credit Portfolio	3,359		3,389
Barings European Loan Fund Buy & Hold	7,125		6,622
	$	36,198	$	34,612

Schedule of Annual Benefit Payments which Reflect Expected Future Service

The following annual benefit payments, which reflect expected future service as appropriate, are expected to be paid.


	(in thousands)
2022	$	256
2023	340
2024	417
2025	453
2026	788
Years 2027 - 2031	3,859

Equity Incentive Schemes and Stock Compensation Charges (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Transactions for Company's Share Option Plans

The following table summarizes the transactions for the Company's share option plans for the years ended December 31, 2021, December 31, 2020 and December 31, 2019:


	Options Granted Under Plans	Weighted Average Exercise Price
Outstanding at December 31, 2018	920,746	$	74.32
Granted	97,112	$	140.13
Exercised	(329,870)	$	65.54
Canceled	(31,881)	$	88.12
Outstanding at December 31, 2019	656,107	$	87.80
Granted	107,737	$	159.83
Exercised	(193,417)	$	68.19
Canceled/expired	(16,681)	$	92.21
Outstanding at December 31, 2020	553,746	$	108.53
Assumed through business combinations *	2,177,130	$	108.78
Granted	100,299	$	177.76
Exercised	(1,065,529)	$	111.29
Canceled/expired	(70,186)	$	128.46
Outstanding at December 31, 2021	1,695,460	$	104.79
Vested and exercisable at December 31, 2021	989,419	$	91.70

*Represents stock options issued as replacement awards in connection with the Merger.

Schedule of Non Vested Shares Outstanding

Summary of Information Concerning Outstanding and Exercisable Share Options

The following table summarizes information concerning outstanding and exercisable share options as of December 31, 2021:


Options Outstanding					Options Exercisable
Range Exercise Price	Number of Shares	Weighted Average Remaining Contractual Life	Weighted Average Exercise Price		Number of Shares	Weighted Average Exercise Price

14.80 - 97.30	638,118	3.45			605,624
103.81 - 124.00	320,310	6.49			130,920
125.74 - 147.26	540,296	6.56			235,808
159.33 - 231.08	196,736	6.68			17,067

14.80 - 231.08	1,695,460	5.39	$	104.79	989,419	$	91.70

Summary of Weighted Average Fair Values and Assumptions Used

The weighted average fair values and assumptions were as follows:


	Year Ended
	December 31, 2021			December 31, 2020			December 31, 2019
Weighted average fair value	$	49.15		$	42.43		$	43.43

Assumptions:
Expected volatility	30		%	30		%	30		%
Dividend yield	—		%	—		%	—		%
Risk-free interest rate	0.78		%	0.57		%	2.55		%
Expected life	5.0 years			5.0 years			5.0 years


	July 1, 2021
Weighted average grant date fair value	$	107.21
Assumptions:
Expected volatility	30		%
Dividend yield	—		%
Risk-free interest rate	0.56		%
Expected life	3.5 years

Summary of RSU and PSU Activity

The following table summarizes RSU and PSU activity for the year ended December 31, 2021:


	PSU Outstanding Number of Shares	PSU Weighted Average Grant Date Fair Value		RSU Outstanding Number of Shares	RSU Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020	159,641	$	137.64	341,424	$	145.77

Assumed through business combination*	—	$	—	589,517	$	206.71
Granted	55,444	$	177.77	171,316	$	214.36
Shares vested **	(44,132)	$	115.61	(446,404)	$	186.99
Forfeited	(16,763)	$	141.36	(83,068)	$	188.49

Outstanding at December 31, 2021	154,190	$	160.23	572,785	$	191.20

* Represents restricted stock units issued as replacement awards in connection with the Merger.

** Includes 161,389 RSU's which vested on the date of the Merger.

Schedule of Non-cash Stock Compensation Expense

Non-cash stock compensation expense has been allocated as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Direct costs	$	18,551	$	8,557	$	14,777
Selling, general and administrative	41,457		17,714		12,042
Transaction and integration related *	73,836		—		—
Total compensation costs	$	133,844	$	26,271	$	26,819

* Represents the post combination portion of the accelerated vesting of awards following the completion of the Merger

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Summary of Components of Income Before Provision for Income Taxes

The components of income before income tax expense are as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Ireland	$	231,893	$	280,310	$	323,726
United States	(278,413)		41,950		21,073
Other	243,200		58,945		82,190
Income before income tax expense	$	196,680	$	381,205	$	426,989

Summary of Components of Provision for Income Taxes

The components of income tax expense are as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Income tax expense:
Current tax expense:
Ireland	$	18,469	$	28,963	$	35,955
United States	35,478		3,022		5,073
Other	48,003		14,963		11,642
Total current tax expense	101,950		46,948		52,670

Deferred tax (benefit)/expense:
Ireland	553		1,654		2,833
United States	(52,717)		4,577		(3,502)
Other	(8,452)		(5,304)		(868)
Total deferred tax (benefit)/expense	(60,616)		927		(1,537)

Income tax expense allocated to continuing operations	41,334		47,875		51,133

Income tax expense was allocated to the following components of other comprehensive income:

Currency impact on long term funding	49		68		25


Total	$	41,383	$	47,943	$	51,158

Schedule of Reconciliation of Consolidated Reported Provision for Income Taxes and Statutory Rate

The Company's consolidated reported income tax expense differed from the amount that would result from applying the Irish statutory rate as set forth below:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Taxes at Irish statutory rate of 12.5% (2021:12.5%; 2020:12.5%)	$	24,586	$	47,651	$	53,374
Foreign and other income taxed at higher rates	20,045		7,943		7,356
Research & development tax incentives	(3,120)		(1,243)		(893)
Movement in valuation allowance	3,101		3,581		(10)
Effects of change in tax rates	(128)		108		359
Change in unrecognized tax benefits	5,246		(1,672)		(1,273)
Impact of stock compensation	(9,083)		(5,150)		(7,383)

Other	687		(3,343)		(397)
Income tax expense	$	41,334	$	47,875	$	51,133

Schedule of Tax Effects of Temporary Differences that Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and deferred tax liabilities are presented below:


	December 31, 2021		December 31, 2020
	(in thousands)
Deferred tax liabilities:
Property, plant and equipment	$	19,606	$	1,359
Right-of-use-assets	33,449		9,402
Goodwill	33,354		31,629
Intangible assets	1,201,086		13,398
Other	1,761		1,009
Total deferred tax liabilities recognized	1,289,256		56,797

Deferred tax assets:
Operating loss and tax credits carryforwards	86,893		42,794
Property, plant and equipment	5,846		6,040
Lease liabilities	36,106		9,394
Intangible assets	4,596		—
Accrued expenses and unbilled revenue	69,198		24,368
Stock compensation	25,557		3,672
Deferred compensation	3,445		3,184
Unearned revenue	64,924		2,257
Other	602		155
Total deferred tax assets	297,167		91,864
Valuation allowance for deferred tax assets	(45,495)		(32,768)
Deferred tax assets recognized	251,672		59,096
Overall net deferred tax asset/(liability)	$	(1,037,584)	$	2,299

Schedule of Expected Expiry Dates of NOL's

The expected expiry dates of these US losses are as follows:


	Federal NOL's		State NOL's
	(in thousands)
2022-2035	$	10,238	$	227,538
2036-2040	16		25,073
Indefinite	95		44,370

	$	10,349	$	296,981

Schedule of Reconciliation of Beginning and Ending Amount of Total Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of total unrecognized tax benefits is as follows:


	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Unrecognized tax benefits at start of year	$	19,078	$	20,156	$	21,433
Increase related to acquired tax positions	170,047		—		—
Increase related to prior year tax positions	204		401		—
Decrease related to prior year tax positions	(1,695)		(1,271)		—
Increase related to current year tax positions	18,613		2,931		1,588
Settlements	(844)		(369)		(347)
Lapse of statute of limitations	(3,338)		(2,770)		(2,518)
Unrecognized tax benefits at end of year	$	202,065	$	19,078	$	20,156

Restructuring charges (Tables)

12 Months Ended

Dec. 31, 2021

Restructuring and Related Activities [Abstract]

Schedule of Restructuring Charges


	Year Ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Restructuring charges	$	31,105	$	18,089	$	—
Net charge	$	31,105	$	18,089	$	—

Schedule of Restructuring Reserve by Type of Cost


	Year Ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)

Opening provision	$	10,748	$	1,637	$	6,419
Additional provision in the year	26,674		18,089		—
Utilization	(9,069)		(8,978)		(4,782)
Ending provision	$	28,353	$	10,748	$	1,637

Disaggregation of Revenue (Tables)

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

Revenue disaggregated by customer profile is as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Top client	$	441,173	$	337,904	$	350,287
Clients 2-5	1,291,946		754,906		704,963
Clients 6-10	752,325		350,865		347,832
Clients 11-25	1,077,073		501,643		529,713
Other	1,918,309		851,970		873,044
Total	$5,480,826		$2,797,288		$2,805,839

Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) (Tables)

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Schedule of Contracts with Customers, Asset and Liabilities

Accounts receivable and unbilled revenue are as follows:


	December 31, 2021		December 31, 2020
	(in thousands)
Billed services (accounts receivable)	$	1,349,851	$	722,420
Allowance for credit losses (note 19)	(7,081)		(7,149)
Accounts receivable (net)	1,342,770		715,271
Unbilled services (unbilled revenue)	$	623,121	$	428,684
Accounts receivable and unbilled revenue, net	$	1,965,891	$	1,143,955

Unbilled services and unearned revenue or payments on account (contract assets and liabilities) were as follows:


(in thousands, except percentages)	December 31, 2021		December 31, 2020		$ Change		% Change

Unbilled services (unbilled revenue)	$	623,121	$	428,684	$	194,437	45.4	%
Unearned revenue (payments on account)	(1,323,961)		(660,883)		(663,078)		100.3	%
Net balance	$	(700,840)	$	(232,199)	$	(468,641)	(201.8)	%

Provision for Credit Losses (Tables)

12 Months Ended

Dec. 31, 2021

Accounts Receivable, after Allowance for Credit Loss [Abstract]

Schedule of Provision for Credit Losses

The Company does business with most major international pharmaceutical companies. Provision for credit losses at December 31, 2021 and December 31, 2020 comprises:


	December 31, 2021		December 31, 2020
	(in thousands)
Opening provision	$	7,149	$	7,380
Amounts used during the year	(116)		(2,561)
Amounts provided during the year	705		2,692
Amounts released during the year	(544)		(510)
Foreign exchange	(113)		148
Closing provision	$	7,081	$	7,149

Business Segment and Geographical Information (Tables)

12 Months Ended

Dec. 31, 2021

Segment Reporting [Abstract]

Schedule of Distribution of Net Revenue by Geographical Area

The distribution of revenue by geographical area was as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019

	(in thousands)
Ireland	$	1,365,909	$	1,181,292	$	1,252,834
Rest of Europe	1,175,515		416,884		388,916
U.S.	2,581,007		925,563		892,497
Other	358,395		273,549		271,592
Total	$	5,480,826	$	2,797,288	$	2,805,839

Schedule of Distribution of Income from Operations by Geographical Area

b) The distribution of income from operations, excluding restructuring, transaction and integration related expenses, by geographical area was as follows:


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Ireland *	$	161,862	$	295,360	$	314,287
Rest of Europe	183,436		35,402		37,997
U.S.	231,971		56,921		60,272
Other	30,628		21,147		20,850
Total	$	607,897	$	408,830	$	433,406

* Includes the full amount of the amortization charge associated with the intangible asset acquired in the Merger. These assets have been provisionally allocated to Ireland.

Schedule of Distribution of Long-lived Assets, Net, by Geographical Area

The distribution of long-lived assets (property, plant and equipment and operating right-of-use assets), net, by geographical area was as follows:


	December 31, 2021		December 31, 2020
	(in thousands)
Ireland	$	118,253	$	118,361
Rest of Europe	121,174		36,723
U.S.	239,828		65,152
Other	55,312		38,668
Total	$	534,567	$	258,904

Supplemental Disclosure of Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2021

Supplemental Cash Flow Elements [Abstract]

Schedule of Supplemental Disclosure of Cash Flow Information


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Cash paid for interest	$	106,205	$	13,062	$	13,059
Cash paid for income taxes (net of refunds)	$	55,105	$	27,604	$	29,836

Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2021

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule of Accumulated Other Comprehensive Income


	Year ended
	December 31, 2021		December 31, 2020
	(in thousands)
Currency translation adjustments	$	(75,986)	$	(15,894)
Currency impact on long term funding	(9,854)		(9,329)
Actuarial loss on defined benefit pension plan (note 10)	(5,098)		(9,364)

Realized gain on interest rate hedge	—		4,658
Amortization of gain on interest rate hedge	—		(4,658)
Loss on interest rate hedge	—		(905)

Amortization of loss on interest rate hedge	1		15
Total	$	(90,937)	$	(35,477)

Operating Leases (Tables)

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Lease Cost

Lease costs recorded under operating leases were as follows:


	Year ended
	December 31, 2021		December 31, 2020
	(in thousands)

Operating lease costs	$	51,200	$	31,088
Income from sub-leases	(1,338)		(940)
Net operating lease costs	$	49,862	$	30,148

Schedule of Operating Lease Maturity

Future minimum lease payments under non-cancelable leases as of December 31, 2021 were as follows:


	Minimum rental
	payments
	(in thousands)
2022	$	54,292
2023	45,469
2024	29,607
2025	20,758
2026	17,714
Thereafter	59,858
Total future minimum lease payments	227,698
Lease imputed interest	(18,266)
Total	$	209,432

Non-current bank credit lines and loan facilities (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

The Company had the following debt outstanding as of December 31, 2021 and December 31, 2020:


			Principal amount
	Interest rate as of		December 31,		December 31,
(in thousands)	December 31, 2021		2021		2020		Maturity Date
Senior Secured Credit Facility
Term loan	2.75	%	$	5,001,213	$	—	July 2028

Senior Secured Notes	2.875	%	500,000		—		July 2026
2020 Senior Notes:
Series A notes			—		275,000
Series B notes			—		75,000
Total debt			5,501,213		350,000

Less current portion of long-term debt			(55,150)		—
Total long-term debt			5,446,063		350,000
Less debt issuance costs and debt discount			(64,901)		(1,523)
Total long-term debt, net			$	5,381,162	$	348,477

Schedule of Financing Cost


	Year ended
	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)

Interest expense on drawn facilities	$	93,809	$	13,406	$	13,659
Amortization of financing costs	12,890		523		540
Transaction and one time financing costs	75,391		—		—
Other financing costs/(credits)	333		(910)		(923)
Total financing costs	$	182,423	$	13,019	$	13,276

Schedule of Maturities of Long-term Debt

As of December 31, 2021, the contractual maturities of the Company's debt obligations were as follows:


Current maturities of long-term debt:	(in thousands)
2022	55,150
2023	55,150
2024	55,150
2025	55,150
2026 and thereafter	5,280,613
Total	$	5,501,213

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

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-Name Accounting Standards Codification
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-Subparagraph (SX 210.12-04(a))
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Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

Net Income Per Ordinary Share (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Reconciliation of Number of Shares Used in Computation of Basic and Diluted Net Income Per Ordinary Share

The reconciliation of the number of shares used in the computation of basic and diluted net income per ordinary share is as follows:


	December 31, 2021	December 31, 2020	December 31, 2019
Weighted average number of ordinary shares outstanding for basic net income per ordinary share	67,110,186	52,859,911	53,859,537
Effect of dilutive share options outstanding	958,125	423,674	473,924
Weighted average number of ordinary shares outstanding for diluted net income per ordinary share	68,068,311	53,283,585	54,333,461

Reconciliation of Net Income Attributable to the Group Per the Statement of Operating Income and Net Income Used For Net Income Per Ordinary Share


	December 31, 2021		December 31, 2020		December 31, 2019
	(in thousands)
Net income attributable to the Group	$	153,185	332,331		$	373,986
Noncontrolling interest adjustment to redemption amount	—		(4,522)		(5,048)
Net income attributable to the Group (including NCI redemption adjustment)	153,185		327,809		368,938

	December 31, 2021		December 31, 2020		December 31, 2019
Net income per Ordinary Share attributable to the Group (including NCI redemption adjustment):
Basic	$	2.28	$	6.20	$	6.85
Diluted	$	2.25	$	6.15	$	6.79

Description of business (Details)	12 Months Ended
Description of business (Details)	Dec. 31, 2021 Location Country
Product Information [Line Items]
Number of locations in which company operates \| Location	142
Number of countries in which company operates \| Country	53
Geographic Concentration Risk \| United States \| Net Revenue
Product Information [Line Items]
Percentage of company revenue (in percent)	47.10%
Geographic Concentration Risk \| Europe \| Net Revenue
Product Information [Line Items]
Percentage of company revenue (in percent)	46.40%
Geographic Concentration Risk \| Rest of World \| Net Revenue
Product Information [Line Items]
Percentage of company revenue (in percent)	6.50%

Significant accounting policies - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 09, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment charge	$ 0	$ 0	$ 0
Carrying value of inventory	$ 5,800,000	$ 4,800,000
MeDiNova
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Business combination acquisition percentage (in percent)				100.00%

Significant accounting policies - Adjustments Resulting from Foreign Currency Translation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Foreign Currency [Abstract]
Amounts (credited)/charged	$ (14,316)	$ 5,979	$ 590

Significant accounting policies - Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2021
Building
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years
Computer equipment and software \| Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Computer equipment and software \| Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	8 years
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated useful lives	8 years
Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Motor vehicles
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

Investments - Available For Sale Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation Of Debt Securities, Available-For-Sale [Roll Forward]
Available for sale investments at start of year	$ 1,729	$ 49,628
Purchases	480	0	$ 9,603
Sales and maturities	(497)	(47,902)	(21,686)
Realized gain on sale of short term investments	0	234
Unrealized capital (loss)/gain - investments	0	(231)	681
Available for sale investments at end of year	$ 1,712	$ 1,729	$ 49,628

Investments - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended			36 Months Ended	48 Months Ended
Investments - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2021	Jul. 24, 2020
Related Party Transaction [Line Items]
Short term investments average maturity period	2 years 8 months 12 days	3 years 4 months 24 days
Purchase of investments in equity - long term	$ 3,577	$ 3,212	$ 3,890	$ 13,300	$ 16,900
Increase in fair value	3,200	2,500
Carrying value of long-term investments in equity	22,600	15,800		15,800	22,600
Commitment to acquire future long-term investments	17,400				17,400
Equity method investments (Note 3c)	$ 2,373	4,534		$ 4,534	$ 2,373	$ 4,900
Ownership percentage	49.00%				49.00%
Majority investor, ownership percentage	51.00%				51.00%
Period majority voting share capital can be sold to the company	18 months
Loss on equity method investments	$ 2,161	$ 366	$ 0
Oncacare
Related Party Transaction [Line Items]
Loan granted tp related party	$ 10,000
Related party, loan interest rate	1.60%

Investments - Available For Sale Short Term Investments by Major Security Type (Details) $ in Millions	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Cost Total	$ 1.7
Fair Value Total	1.7
Less than 1 year	0.5
1 to 5 years	1.2
Term deposits
Debt Securities, Available-for-sale [Line Items]
Cost Total	1.7
Fair Value Total	1.7
Less than 1 year	0.5
1 to 5 years	$ 1.2

Investments - Equity Method Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Jul. 24, 2020
Investments, Debt and Equity Securities [Abstract]
Ownership percentage	49.00%
Equity method investments	$ 2,373	$ 4,534	$ 4,900

Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Opening goodwill	$ 936,257	$ 883,170
Current year acquisitions (note 6)	8,120,006	27,191
Prior period acquisition	0	123
Foreign exchange movement	(18,332)	25,773
Closing goodwill	$ 9,037,931	$ 936,257

Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Total cost	$ 5,081,381	$ 200,011
Accumulated amortization	(370,538)	(133,551)
Net book value	4,710,843	66,460
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Total cost	4,056,642	144,251
Order backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Total cost	528,022	39,269
Trade names & brands
Acquired Finite-Lived Intangible Assets [Line Items]
Total cost	204,685	2,766
Patient database
Acquired Finite-Lived Intangible Assets [Line Items]
Total cost	170,525	2,552
Technology assets
Acquired Finite-Lived Intangible Assets [Line Items]
Total cost	$ 121,507	$ 11,173

Intangible Assets - Narrative (Details) - USD ($) $ in Thousands			6 Months Ended	12 Months Ended
	Jul. 01, 2021	Jan. 22, 2020	Dec. 31, 2021	Dec. 31, 2021
PRA Health Sciences, Inc
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired	$ 4,886,000
Amortization of intangible assets			$ 223,500
PRA Health Sciences, Inc \| Minimum
Indefinite-lived Intangible Assets [Line Items]
Amortization period	3 years
PRA Health Sciences, Inc \| Maximum
Indefinite-lived Intangible Assets [Line Items]
Amortization period	23 years
PRA Health Sciences, Inc \| Customer relationships
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired	$ 3,915,000
PRA Health Sciences, Inc \| Order backlog
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired	490,000
PRA Health Sciences, Inc \| Trade names & brands
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired	202,000
PRA Health Sciences, Inc \| Patient database
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired	168,000
PRA Health Sciences, Inc \| Technology assets
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired	$ 111,000
Medpass Group Limited
Indefinite-lived Intangible Assets [Line Items]
Amortization of intangible assets				$ 2,000
Percentage of share capital acquired (in percent)		100.00%
Medpass Group Limited \| Customer relationships
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired		$ 11,725
Amortization period		13 years
Medpass Group Limited \| Order backlog
Indefinite-lived Intangible Assets [Line Items]
Value of intangible assets acquired		$ 2,883
Amortization period		3 years

Intangible Assets - Future Intangible Asset Amortization Expense (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 456,973
2023	454,235
2024	338,463
2025	222,191
2026	208,175
Finite lived intangible assets, amortization expense, net, total	$ 1,680,037

Business combinations - Narrative, PRA Acquisition (Details) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended	12 Months Ended
	Jul. 01, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Transaction and integration related (Note 6)			$ 198,263	$ (759)	$ 4,085
Total financing costs			182,423	13,019	13,276
Transaction and one time financing costs			75,391	$ 0	$ 0
PRA Health Sciences, Inc
Business Acquisition [Line Items]
Business acquisition, share price (in USD per share)	$ 80
Business acquisition, number of shares issued (in shares)	0.4125
Transaction and integration related (Note 6)			198,300
Acquisition related costs			57,100
Total financing costs			86,700
Gross debt issuance costs		$ 76,200	76,200
Revenue of acquiree since acquisition date		2,053,400
Pre-tax net income of acquiree since acquisition date		$ 169,900
Transaction and one time financing costs			$ 86,700

Business combinations - Fair Value of Consideration Transferred, PRA Acquisition (Details) - USD ($) $ in Thousands		12 Months Ended
	Jul. 01, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Fair value of cash consideration		$ 5,914,475	$ 47,931	$ 131,272
PRA Health Sciences, Inc
Business Acquisition [Line Items]
Fair value of cash consideration	$ 5,308,646
Fair value of ordinary shares issued to acquiree stockholders	5,658,126
Fair value of replacement share-based awards issued to acquiree employees	209,399
Repayment of term loan obligations and accrued interest	865,800
Consideration transferred	12,041,971
Payments to settle debt obligations that existed prior to acquisition date	$ 401,600

Business combinations - Schedule of Acquisitions, PRA Acquisition (Details) - USD ($)	Dec. 31, 2021	Jul. 01, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 9,037,931,000		$ 936,257,000	$ 883,170,000
PRA Health Sciences, Inc
Business Acquisition [Line Items]
Cash and cash equivalents		$ 259,971,000
Accounts receivable and unbilled revenue		934,308,000
Other current assets		125,156,000
Fixed assets		156,851,000
Operating lease right-of-use assets		177,345,000
Goodwill		8,120,006,000
Intangible assets		4,886,000,000
Deferred tax assets		28,099,000
Other assets		35,391,000
Accounts payable		(50,259,000)
Accrued expenses and other current liabilities		(380,342,000)
Current portion of operating lease liabilities		(36,625,000)
Unearned revenue		(739,278,000)
Non-current portion of operating lease liabilities		(144,403,000)
Deferred tax liabilities		(1,126,952,000)
Other non-current liabilities		(203,297,000)
Net assets acquired		12,041,971,000
Goodwill, expected tax deductible amount		$ 0

Business combinations - Fair Value of Identified Intangible Assets Acquired, PRA Acquisition (Details) - PRA Health Sciences, Inc $ in Thousands	Jul. 01, 2021 USD ($)
Business Acquisition [Line Items]
Estimated Fair Value	$ 4,886,000
Customer relationships
Business Acquisition [Line Items]
Estimated Fair Value	$ 3,915,000
Estimated Useful Life	23 years
Order backlog
Business Acquisition [Line Items]
Estimated Fair Value	$ 490,000
Estimated Useful Life	3 years
Trade names
Business Acquisition [Line Items]
Estimated Fair Value	$ 202,000
Estimated Useful Life	3 years
Patient database
Business Acquisition [Line Items]
Estimated Fair Value	$ 168,000
Estimated Useful Life	7 years
Technology assets
Business Acquisition [Line Items]
Estimated Fair Value	$ 111,000
Estimated Useful Life	5 years

Business combinations - Schedule of Pro-Forma Information, PRA Acquisition (Details) - PRA Health Sciences, Inc - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Revenue	$ 7,462,000	$ 5,980,653
Net income/(loss)	$ 340,942	$ (149,658)

Business combinations - Narrative, MedPass Group Acquisition (Details) - Medpass Group Limited - USD ($) $ in Millions	11 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Jan. 22, 2020
Business Acquisition [Line Items]
Percentage of share capital acquired			100.00%
Accounts receivable adjustment		$ 0.2
Unearned revenue adjustment		0.8
Operating right-to-use assets fair value adjustment		0.8
Other liabilities adjustment		0.8
Operating current lease liabilities fair value adjustment		0.1
Operating non-current lease liabilities fair value adjustment		0.7
Operating non-current deferred tax liability fair value adjustment		$ 0.6
Revenue of acquiree since acquisition date	$ 13.2
Net income of acquiree since acquisition date	$ 2.5

Business combinations - Schedule of Acquisitions, MedPass Group Acquisition (Details) - USD ($)		12 Months Ended
	Jan. 22, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 31, 2021
Business Acquisition [Line Items]
Goodwill		$ 9,037,931,000	$ 936,257,000	$ 883,170,000
Fair value of cash consideration		$ 5,914,475,000	$ 47,931,000	$ 131,272,000
Medpass Group Limited
Business Acquisition [Line Items]
Cash and cash equivalents	$ 10,170,000
Property, plant and equipment	45,000
Operating right of use assets	539,000
Goodwill	27,191,000
Accounts receivable	3,033,000
Prepayments and other current assets	158,000
Accounts payable	(368,000)
Unearned revenue	(989,000)
Other liabilities	(2,202,000)
Current lease liabilities	(219,000)
Non-current portion of operating lease liabilities	(320,000)
Deferred tax liabilities	(4,090,000)
Net assets acquired	47,556,000
Fair value of cash consideration	46,992,000
Working capital adjustment paid	(564,000)
Contingent consideration	0				$ 0
Total consideration	47,556,000
Goodwill, expected tax deductible amount	0
Contingent consideration, range of outcomes, maximum value	6,700,000
Medpass Group Limited \| Customer relationships
Business Acquisition [Line Items]
Intangible assets	11,725,000
Medpass Group Limited \| Order backlog
Business Acquisition [Line Items]
Intangible assets	$ 2,883,000

Business combinations - Schedule of Pro-Forma Information, MedPass Group Acquisition (Details) - Medpass Group Limited - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Revenue	$ 2,798,180	$ 2,820,796
Net income/(loss)	$ 332,521	$ 377,485

Property, Plant and Equipment, net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Land	$ 3,724	$ 3,724
Building	82,017	90,139
Computer equipment and software	506,322	440,930
Office furniture and fixtures	107,507	91,933
Laboratory equipment	29,210	44,567
Leasehold improvements	70,123	32,261
Motor vehicles	65	160
Property, plant and equipment, gross	798,968	703,714
Less accumulated depreciation and asset write offs	(462,524)	(529,371)
Property, plant and equipment (net)	$ 336,444	$ 174,343

Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Other Liabilities Disclosure [Abstract]
General trade and overhead liabilities	$ 459,814	$ 188,638
Personnel related liabilities	413,185	161,363
Operating lease liabilities (note 23)	49,949	24,334
Facility related liabilities	12,055	9,441
Other liabilities	7,204	8,726
Restructuring liabilities (note 15)	7,377	7,219
Short term government grants	45	48
Other liabilities	949,629	399,769
Amounts due to third parties for reimbursable expenses	$ 323,600	$ 138,200

Non-Current Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Defined benefit pension obligations, net (note 10)	$ 16,262	$ 10,395
Other non-current liabilities	25,599	15,971
Non-current other liabilities (Note 9)	$ 41,861	$ 26,366

Employee Benefits - Narrative (Details) - USD ($)	12 Months Ended
Employee Benefits - Narrative (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	May 07, 2014
Other retirement plans
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	$ 8,000,000
ICON Development Solutions Limited pension plan
Defined Benefit Plan Disclosure [Line Items]
44561	3.80%
ICON Development Solutions Limited pension plan \| Secured Loans and Multi Asset Credit
Defined Benefit Plan Disclosure [Line Items]
Percentage of investments (in percent)	20.00%
44561	3.00%	3.00%
ICON Development Solutions Limited pension plan \| Corporate Bonds (including 50% high yield bonds)
Defined Benefit Plan Disclosure [Line Items]
Percentage of investments (in percent)	18.00%
44561	2.80%	2.80%
ICON Development Solutions Limited pension plan \| High yield bonds
Defined Benefit Plan Disclosure [Line Items]
Percentage of investments (in percent)	19.00%
ICON Development Solutions Limited pension plan \| Equities
Defined Benefit Plan Disclosure [Line Items]
Percentage of investments (in percent)	24.00%
44561	5.50%	5.20%
United States
Defined Benefit Plan Disclosure [Line Items]
Participant's contributions percentage of annual compensation (in percent)	4.50%
Defined contribution plan, cost	$ 23,700,000	$ 17,000,000	$ 16,500,000
United Kingdom \| ICON Development Solutions Limited pension plan
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	41,813,000	$ 43,988,000	$ 37,036,000
Net loss that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	200,000
Net prior service cost for defined benefit pension plan that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	$ 0
Pension plan period	26 years
44561	3.40%	4.00%	2.10%
Contribution to pension fund in the year ending December 31, 2021	$ 100,000
Retirement period used as a basis to estimate expected cash flows	10 years
Switzerland \| Aptiv Solutions pension plan
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	$ 7,643,000	$ 8,620,000	$ 7,047,000
Switzerland \| Aptiv Solutions pension plan \| Aptiv Solutions
Defined Benefit Plan Disclosure [Line Items]
Percentage of share capital acquired (in percent)				100.00%

Employee Benefits - Funded Status (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
United Kingdom \| ICON Development Solutions Limited pension plan
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ (41,813)		$ (43,988)
Fair value of plan assets	36,198		34,612	$ 32,016
Funded status	(5,615)		(9,376)
Non-current other liabilities (note 9)	(5,615)		(9,376)
United Kingdom \| PRA Switzerland AG pension plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,017	$ 2,849
Switzerland \| Aptiv Solutions pension plan
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	(7,643)		(8,620)
Fair value of plan assets	6,964		7,601	$ 6,014
Funded status	(679)		(1,019)
Non-current other liabilities (note 9)	(679)		$ (1,019)
Switzerland \| PRA Switzerland AG pension plan
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	(4,990)
Fair value of plan assets	3,017
Funded status	(1,973)
Non-current other liabilities (note 9)	$ (1,973)

Employee Benefits - Change in Benefit Obligations (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
United Kingdom \| ICON Development Solutions Limited pension plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year		$ 43,988	$ 37,036
Service cost		134	100	$ 107
Interest cost		665	746	867
Plan participants' contributions		23	22
Benefits paid		(489)	(724)
Actuarial (gain)/loss		(2,097)	5,294
Foreign currency exchange rate changes		(411)	1,514
Benefit obligation at end of year	$ 41,813	41,813	43,988	37,036
Switzerland \| Aptiv Solutions pension plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year		8,620	7,047
Service cost		150	139
Interest cost		12	21
Plan participants' contributions		95	81
Settlement		483	0
Prior service cost		(82)	(23)
Transferred balances		76	(245)
Actuarial (gain)/loss		(484)	406
Foreign currency exchange rate changes		(261)	704
Benefit obligation at end of year	7,643	7,643	$ 8,620	$ 7,047
Switzerland \| PRA Switzerland AG pension plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	4,890
Service cost	207
Interest cost	19
Plan participants' contributions	135
Benefits paid	(113)
Actuarial (gain)/loss	1
Foreign currency exchange rate changes	(149)
Benefit obligation at end of year	$ 4,990	$ 4,990

Employee Benefits - Change in Plan Assets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
United Kingdom \| ICON Development Solutions Limited pension plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year		$ 34,612	$ 32,016
Expected return on plan assets		1,171	1,214	$ 574
Actual return on plan assets		2,347	2,092
Employer contributions		91	109
Plan participants' contributions		23	22
Benefits paid		(489)	(724)
Foreign currency exchange rate changes		(386)	1,097
Fair value of plan assets at end of year	$ 36,198	36,198	34,612	32,016
United Kingdom \| PRA Switzerland AG pension plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,849
Actual return on plan assets	15
Employer contributions	135
Plan participants' contributions	135
Benefits paid	(113)
Foreign currency exchange rate changes	(4)
Fair value of plan assets at end of year	3,017	3,017
Switzerland \| Aptiv Solutions pension plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year		7,601	6,014
Expected return on plan assets		15	21
Actual return on plan assets		(238)	519
Scheme contributions		128	105
Plan participants' contributions		95	81
Transferred balances		76	245
Settlement		(483)	0
Foreign currency exchange rate changes		(230)	616
Fair value of plan assets at end of year	6,964	6,964	$ 7,601	$ 6,014
Switzerland \| PRA Switzerland AG pension plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at end of year	$ 3,017	$ 3,017

Employee Benefits - Components of Net Periodic Benefit Cost (Details) - United Kingdom - ICON Development Solutions Limited pension plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 134	$ 100	$ 107
Interest cost	665	746	867
Expected return on plan assets	(1,171)	(1,214)	(574)
Amortization of net loss	625	160	67
Net periodic benefit cost	$ 253	$ (208)	$ 467

Employee Benefits - Net Periodic Pension Benefit Cost Assumptions (Details) - ICON Development Solutions Limited pension plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Expected rate of return on plan assets	3.80%
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.50%	2.10%	2.90%
Rate of compensation increase	3.40%	3.30%	3.70%
Expected rate of return on plan assets	3.40%	4.00%	2.10%
Other comprehensive income
Actuarial (gain)/loss - benefit obligation	$ (2,097)	$ 5,294	$ 4,756
Actuarial gain – plan assets	(1,176)	(878)	(2,930)
Actuarial loss recognized in net periodic benefit cost	(625)	(160)	(67)
Total	$ (3,898)	$ 4,256	$ 1,759

Employee Benefits - Assumptions Used in Determining Benefit Obligation (Details) - United Kingdom - ICON Development Solutions Limited pension plan	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.80%	1.50%
Rate of compensation increase	3.70%	3.40%

Employee Benefits - Expected Rate of Return and Actual Plan Asset Allocation (Details) - ICON Development Solutions Limited pension plan	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
High yield percentage of corporate bond investment	50.00%
44561	3.80%
Actual plan asset allocations	100.00%	100.00%
Corporate Bonds (including 50% high yield bonds)
Defined Benefit Plan Disclosure [Line Items]
44561	2.80%	2.80%
Actual plan asset allocations	37.00%	40.00%
Equities
Defined Benefit Plan Disclosure [Line Items]
44561	5.50%	5.20%
Actual plan asset allocations	24.00%	21.00%
Secured Loans and Multi Asset Credit
Defined Benefit Plan Disclosure [Line Items]
44561	3.00%	3.00%
Actual plan asset allocations	39.00%	39.00%
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
44561	3.40%	4.00%	2.10%

Employee Benefits - Plan Asset Fair Value Measurements (Details) - ICON Development Solutions Limited pension plan - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
High yield percentage of corporate bond investment	50.00%
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 36,198	$ 34,612
Fair Value, Inputs, Level 1 \| Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	162	11
Fair Value, Inputs, Level 1 \| L&G Life GPBF All World Equity Index Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,743	7,460
Fair Value, Inputs, Level 1 \| L&G Life DC Active Corporate Bond
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,409	6,797
Fair Value, Inputs, Level 1 \| Stone Harbor High Yield Bond Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,965	6,861
Fair Value, Inputs, Level 1 \| Ninety One Global Total Return Credit
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,435	3,472
Fair Value, Inputs, Level 1 \| Stone Harbor Multi Asset Credit Portfolio
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,359	3,389
Fair Value, Inputs, Level 1 \| Barings European Loan Fund Buy & Hold
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 7,125	$ 6,622

Employee Benefits - Annual Benefit Payments (Details) - United Kingdom - ICON Development Solutions Limited pension plan $ in Thousands	Dec. 31, 2021 USD ($)
Defined Benefit Plan Disclosure [Line Items]
2022	$ 256
2023	340
2024	417
2025	453
2026	788
Years 2027 - 2031	$ 3,859

Equity Incentive Schemes and Stock Compensation Charges - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended			24 Months Ended	252 Months Ended
	Feb. 14, 2017	May 11, 2015	Jan. 17, 2003	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2017	May 18, 2020	May 16, 2019	May 31, 2018	Feb. 13, 2017	Sep. 23, 2013
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Weighted average contractual term of options outstanding				5 years 4 months 20 days	4 years 10 months 9 days
Exercisable - weighted average remaining contractual life				4 years 6 months 18 days	3 years 7 months 6 days
Total compensation costs				$ 133,844	$ 26,271	$ 26,819
Income tax benefit related to stock compensation				22,700	6,900	8,200
Cash tax benefit related to stock options exercised				$ 23,900	2,500	$ 1,900
The 2020 Legacy PRA Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)									2,500,000
The 2018 Legacy PRA Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)											2,000,000
2013 Legacy PRA Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)													2,052,909
Percentage of outstanding shares authorized													12.50%
Consultants Stock Plan, 2008 Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)	1,000,000											400,000
Limit of shares issued or to be issued pursuant to options granted (in shares)	1,000,000
Employee Stock Plan, 2008 Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)	6,000,000
Maximum number of shares per employee (in shares)	400,000
Option Plans 2008 \| Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Percentage of option price for fair value of ordinary share (in percent)	100.00%
Employee Stock Plan, 2003 Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)			6,000,000
Maximum number of shares per employee (in shares)			400,000
Maximum number of award as percentage of shares outstanding (in percent)			10.00%
Employee Stock Option \| Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares vesting period				5 years
Employee Stock Option \| Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares vesting period				8 years
Employee Stock Option \| Award date, prior to 2018
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares vesting period								5 years
Shares expiration period								8 years
Employee Stock Option \| Award date, 2018 and thereafter
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares vesting period						12 months
Shares expiration period						8 years
Restricted Stock Units 2013
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)		4,100,000
Additional number of ordinary shares which have been reserved for issuance (in shares)		2,500,000
Consultants Restricted Stock Units 2019
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Ordinary shares which have been reserved for issuance (in shares)										250,000
Consultants Restricted Stock Units 2019 \| Non-executive director
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares vesting period							12 months
Restricted Stock Units (RSUs)
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Fair value of stock units vested				$ 83,500	$ 14,300
Restricted Stock Units (RSUs) \| Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share price of equity instruments other than options, vested in period (in USD per share)				$ 115.11	$ 83.47		$ 83.47
Restricted Stock Units (RSUs) \| Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share price of equity instruments other than options, vested in period (in USD per share)				$ 206.71	$ 156.21		156.21
Performance Share Unit (PSUs)
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Fair value of stock units vested				$ 5,100	$ 5,300
Performance Share Unit (PSUs) \| Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share price of equity instruments other than options, vested in period (in USD per share)				$ 115.11	$ 83.47		83.47
Performance Share Unit (PSUs) \| Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share price of equity instruments other than options, vested in period (in USD per share)				$ 125.74	$ 90.03		$ 90.03
PSUs Based on Service and EPS Targets \| Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Stock units to be granted (in shares)				71,890

Equity Incentive Schemes and Stock Compensation Charges - Summary of Stock Option Activity (Details) - Stock Option and Award Plans - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Options Granted Under Plans
Beginning balance (in shares)	553,746	656,107	920,746
Assumed through business combination (in shares)	2,177,130
Granted (in shares)	100,299	107,737	97,112
Exercised (in shares)	(1,065,529)	(193,417)	(329,870)
Canceled/expired (in shares)	(70,186)	(16,681)	(31,881)
Ending balance (in shares)	1,695,460	553,746	656,107
Vested and exercisable at end of period (in shares)	989,419
Weighted Average Exercise Price
Beginning balance (USD per share)	$ 108.53	$ 87.80	$ 74.32
Assumed through business combination (USD per share)	108.78
Granted (USD per share)	177.76	159.83	140.13
Exercised (USD per share)	111.29	68.19	65.54
Canceled/expired (USD per share)	128.46	92.21	88.12
Ending balance (USD per share)	104.79	$ 108.53	$ 87.80
Vested and exercisable at end of period (USD per share)	$ 91.70

Equity Incentive Schemes and Stock Compensation Charges - Outstanding and Exercisable Share Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Range Exercise Price (USD per share)	$ 14.80
Maximum Range Exercise Price (USD per share)	231.08
Range 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Range Exercise Price (USD per share)	14.80
Maximum Range Exercise Price (USD per share)	97.30
Range 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Range Exercise Price (USD per share)	103.81
Maximum Range Exercise Price (USD per share)	124.00
Range 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Range Exercise Price (USD per share)	125.74
Maximum Range Exercise Price (USD per share)	147.26
Range 4
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Range Exercise Price (USD per share)	159.33
Maximum Range Exercise Price (USD per share)	$ 231.08
Stock Option and Award Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares (in shares)	1,695,460
Weighted Average Remaining Contractual Life	5 years 4 months 20 days
Weighted average exercise price (USD per share)	$ 104.79	$ 108.53	$ 87.80	$ 74.32
Number of Shares (in shares)	989,419
Vested and exercisable at end of period (USD per share)	$ 91.70
Stock Option and Award Plans \| Range 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares (in shares)	638,118
Weighted Average Remaining Contractual Life	3 years 5 months 12 days
Number of Shares (in shares)	605,624
Stock Option and Award Plans \| Range 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares (in shares)	320,310
Weighted Average Remaining Contractual Life	6 years 5 months 26 days
Number of Shares (in shares)	130,920
Stock Option and Award Plans \| Range 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares (in shares)	540,296
Weighted Average Remaining Contractual Life	6 years 6 months 21 days
Number of Shares (in shares)	235,808
Stock Option and Award Plans \| Range 4
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares (in shares)	196,736
Weighted Average Remaining Contractual Life	6 years 8 months 4 days
Number of Shares (in shares)	17,067

Equity Incentive Schemes and Stock Compensation Charges - Schedule of Weighted Average Fair Values and Assumptions Used (Details) - Employee Stock Option - $ / shares		12 Months Ended
	Jul. 01, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value (USD per share)	$ 107.21	$ 49.15	$ 42.43	$ 43.43
Assumptions:
Expected volatility (in percent)	30.00%	30.00%	30.00%	30.00%
Dividend yield (in percent)	0.00%	0.00%	0.00%	0.00%
Risk free interest rate (in percent)	0.56%	0.78%	0.57%	2.55%
Expected life	3 years 6 months	5 years	5 years	5 years

Equity Incentive Schemes and Stock Compensation Charges - Summary of RSU and PSU Activity (Details) - $ / shares		12 Months Ended
	Jul. 01, 2021	Dec. 31, 2021
Performance Share Unit (PSUs)
Outstanding number of shares [Roll Forward]
Outstanding at beginning of period (in shares)		159,641
Assumed through business combination (in shares)		0
Granted (in shares)		55,444
Shares vested (in shares)	(161,389)	(44,132)
Forfeited (in shares)		(16,763)
Outstanding at ending of period (in shares)		154,190
Weighted Average Fair Value
Outstanding at beginning of period (USD per share)		$ 137.64
Assumed through business combination (USD per share)		0
Granted (USD per share)		177.77
Shares vested (USD per share)		115.61
Forfeited (USD per share)		141.36
Outstanding at end of period (USD per share)		$ 160.23
Restricted Stock Units (RSUs)
Outstanding number of shares [Roll Forward]
Outstanding at beginning of period (in shares)		341,424
Assumed through business combination (in shares)		589,517
Granted (in shares)		171,316
Shares vested (in shares)		(446,404)
Forfeited (in shares)		(83,068)
Outstanding at ending of period (in shares)		572,785
Weighted Average Fair Value
Outstanding at beginning of period (USD per share)		$ 145.77
Assumed through business combination (USD per share)		206.71
Granted (USD per share)		214.36
Shares vested (USD per share)		186.99
Forfeited (USD per share)		188.49
Outstanding at end of period (USD per share)		$ 191.20

Equity Incentive Schemes and Stock Compensation Charges - Schedule of Non-cash Stock Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation costs	$ 133,844	$ 26,271	$ 26,819
Direct costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation costs	18,551	8,557	14,777
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation costs	41,457	17,714	12,042
Transaction and integration related *
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation costs	$ 73,836	$ 0	$ 0

Share Capital (Details)			12 Months Ended
Share Capital (Details)	Dec. 31, 2019 USD ($) shares	Jul. 22, 2016	Dec. 31, 2021 USD ($) vote $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) shares	Jan. 08, 2019 shares	Oct. 03, 2016 USD ($)
Equity, Class of Treasury Stock [Line Items]
Number of votes \| vote			1
Total proceeds from exercise of stock options by employees \| $			$ 118,589,000	$ 13,203,000	$ 21,645,000
Ordinary shares redeemed, value \| $				$ 175,000,000	146,931,000
Buyback program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount \| $								$ 400,000,000
Ordinary shares redeemed (in shares)	35,100			1,235,218		4,026,576
Ordinary shares redeemed, value \| $	$ 5,300,000			$ 175,000,000	$ 141,600,000	$ 372,100,000
Number of shares authorized to be repurchased (in shares)							1,000,000
Maximum \| Buyback program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized percentage (in percent)		10.00%
Employee Stock Option
Equity, Class of Treasury Stock [Line Items]
Options exercised by employees (in shares)			1,065,529	193,417	329,870
Average exercise price of option per share (USD per share) \| $ / shares			$ 111.29	$ 68.19	$ 65.54
Total proceeds from exercise of stock options by employees \| $			$ 118,600,000	$ 13,200,000	$ 21,600,000
Restricted Stock Units (RSUs)
Equity, Class of Treasury Stock [Line Items]
Ordinary shares issued in respect of certain RSUs previously awarded by the Company (in shares)			446,404	144,172	237,119
Performance Share Unit (PSUs)
Equity, Class of Treasury Stock [Line Items]
Ordinary shares issued in respect of certain PSUs previously awarded by the Company (in shares)			44,132	63,516	118,611
Ordinary Shares
Equity, Class of Treasury Stock [Line Items]
Issue of shares associated with a business combination (in shares)			27,372,427
Options exercised by employees (in shares)			1,065,529	193,417	329,870
Ordinary shares redeemed (in shares)				1,235,218	1,035,100
Ordinary shares redeemed, value \| $				$ 82,000	$ 69,000

Income Taxes - Components of Income Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]
Income before income tax expense	$ 196,680	$ 381,205	$ 426,989
Ireland
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]
Income before income tax expense	231,893	280,310	323,726
United States
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]
Income before income tax expense	(278,413)	41,950	21,073
Other
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]
Income before income tax expense	$ 243,200	$ 58,945	$ 82,190

Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current tax expense:
Current tax expense	$ 101,950	$ 46,948	$ 52,670
Deferred tax (benefit)/expense:
Deferred tax (benefit)/expense	(60,616)	927	(1,537)
Income tax expense allocated to continuing operations	41,334	47,875	51,133
Income tax expense was allocated to the following components of other comprehensive income:
Currency impact on long term funding	49	68	25
Total	41,383	47,943	51,158
Ireland
Current tax expense:
Current tax expense	18,469	28,963	35,955
Deferred tax (benefit)/expense:
Deferred tax (benefit)/expense	553	1,654	2,833
United States
Current tax expense:
Current tax expense	35,478	3,022	5,073
Deferred tax (benefit)/expense:
Deferred tax (benefit)/expense	(52,717)	4,577	(3,502)
Other
Current tax expense:
Current tax expense	48,003	14,963	11,642
Deferred tax (benefit)/expense:
Deferred tax (benefit)/expense	$ (8,452)	$ (5,304)	$ (868)

Income Taxes - Consolidated Reported Provision for Income Taxes Differed from Statutory Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Taxes at Irish statutory rate of 12.5% (2021:12.5%; 2020:12.5%)	$ 24,586	$ 47,651	$ 53,374
Foreign and other income taxed at higher rates	20,045	7,943	7,356
Research & development tax incentives	(3,120)	(1,243)	(893)
Movement in valuation allowance	3,101	3,581	(10)
Effects of change in tax rates	(128)	108	359
Change in unrecognized tax benefits	5,246	(1,672)	(1,273)
Impact of stock compensation	(9,083)	(5,150)	(7,383)
Other	687	(3,343)	(397)
Income tax expense allocated to continuing operations	$ 41,334	$ 47,875	$ 51,133

Income Taxes - Tax Effects of Temporary Differences That Give Rise to Significant Portions of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Property, plant and equipment	$ 19,606	$ 1,359
Right-of-use-assets	33,449	9,402
Goodwill	33,354	31,629
Intangible assets	1,201,086	13,398
Other	1,761	1,009
Total deferred tax liabilities recognized	1,289,256	56,797
Deferred tax assets:
Operating loss and tax credits carryforwards	86,893	42,794
Property, plant and equipment	5,846	6,040
Lease liabilities	36,106	9,394
Intangible assets	4,596	0
Accrued expenses and unbilled revenue	69,198	24,368
Stock compensation	25,557	3,672
Deferred compensation	3,445	3,184
Unearned revenue	64,924	2,257
Other	602	155
Total deferred tax assets	297,167	91,864
Valuation allowance for deferred tax assets	(45,495)	(32,768)	$ (27,700)
Deferred tax assets recognized	251,672	59,096
Overall net deferred tax asset/(liability)	$ (1,037,584)
Overall net deferred tax asset/(liability)		$ 2,299

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Valuation allowance for deferred tax assets	$ 45,495,000	$ 32,768,000	$ 27,700,000
Net change in the total valuation allowance	12,800,000	5,100,000
Deferred tax liabilities, undistributed foreign earnings	800,000	900,000
Unrecognized tax benefit, potentially expire in 2021	38,800,000
Total unrecognized tax benefits net of potential benefits	202,100,000	19,100,000	20,200,000
Interest and penalties recognized as an expense	1,900,000	600,000	$ 0
Total accrued interest and penalties	15,500,000	500,000
PRA Health Sciences, Inc
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Net change in the total valuation allowance	9,300,000
Provision for income taxes
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Net change in the total valuation allowance	4,400,000	3,600,000
Other Comprehensive Income
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Net change in the total valuation allowance	900,000	$ 1,500,000
Foreign Country
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Other non-U.S subsidiaries operating loss carryforwards for income tax	42,300,000
Foreign Country \| Tax Year 2022 to 2028
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Additional operating loss carryforward	19,900,000
Foreign Country \| Tax Year 2029 to 2038
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Additional operating loss carryforward	19,900,000
Ireland \| Foreign Country
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Ireland subsidiaries additional tax credit carryforward for income tax	14,000,000
United States
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
U.S. Federal net operating loss carry forwards currently available for offset	5,000,000
Alternative minimum tax credit carry forwards	800,000
United States \| Federal NOL's
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Net operating loss carryforwards	10,349,000
U.S. federal net operating loss carry forwards	10,300,000
Tax credit carry forward	145,700,000
Other non-U.S subsidiaries operating loss carryforwards for income tax	95,000
United States \| Tax Year 2022 to 2035 \| Federal NOL's
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
U.S. federal net operating loss carry forwards	10,200,000
Additional operating loss carryforward	10,238,000
United States \| Tax Year 2036-2040 \| Federal NOL's
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
U.S. federal net operating loss carry forwards	100,000
Additional operating loss carryforward	16,000
United States \| State NOL's
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Net operating loss carryforwards	296,981,000
Other non-U.S subsidiaries operating loss carryforwards for income tax	44,370,000
United States \| State NOL's \| Tax Year 2022 to 2035
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Additional operating loss carryforward	227,538,000
United States \| State NOL's \| Tax Year 2036-2040
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Additional operating loss carryforward	25,073,000
Other \| Foreign Country
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Ireland subsidiaries additional tax credit carryforward for income tax	$ 5,300,000

Income Taxes - Expected Expiry Dates of NOL's (Details) - United States $ in Thousands	Dec. 31, 2021 USD ($)
State NOL's
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, not subject to expiration	$ 44,370
Net operating loss carryforwards	296,981
State NOL's \| 2022-2035
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	227,538
State NOL's \| 2036-2040
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	25,073
Federal NOL's
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, not subject to expiration	95
Net operating loss carryforwards	10,349
Federal NOL's \| 2022-2035
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	10,238
Federal NOL's \| 2036-2040
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	$ 16

Income Taxes - Reconciliation of Beginning and Ending Amount of Total Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at start of year	$ 19,078	$ 20,156	$ 21,433
Increase related to acquired tax positions	170,047	0	0
Increase related to prior year tax positions	204	401	0
Decrease related to prior year tax positions	(1,695)	(1,271)	0
Increase related to current year tax positions	18,613	2,931	1,588
Settlements	(844)	(369)	(347)
Lapse of statute of limitations	(3,338)	(2,770)	(2,518)
Unrecognized tax benefits at end of year	$ 202,065	$ 19,078	$ 20,156

Restructuring charges - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 31,105	$ 18,089	$ 0
Impairment of long lived assets	15,400	5,400
Fixed asset impairment	20,037	5,411	0
Restructuring reserve	28,353	10,748	1,637	$ 6,419
Transaction and one time financing costs	75,391	$ 0	$ 0
PRA Health Sciences, Inc
Restructuring Cost and Reserve [Line Items]
Transaction and one time financing costs	86,700
2021 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	31,100
Impairment of long lived assets	21,900
Fixed asset impairment	4,400
Workforce reductions
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	5,200
Workforce reductions \| 2021 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4,800
Lease Liability
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	23,200
Lease Liability \| Other current liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	10,400
Lease Liability \| Other Noncurrent Liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 12,800

Restructuring charges - Summary of Restructuring Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring charges	$ 31,105	$ 18,089	$ 0

Restructuring charges - Restructuring Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Opening provision	$ 10,748	$ 1,637	$ 6,419
Additional provision in the year	26,674	18,089	0
Utilization	(9,069)	(8,978)	(4,782)
Ending provision	$ 28,353	$ 10,748	$ 1,637

Commitments and Contingencies - Narrative (Details)	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Non-cancelable operating leases for facilities expiration period	12 years

Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 5,480,826	$ 2,797,288	$ 2,805,839
Top client
Disaggregation of Revenue [Line Items]
Revenue	441,173	337,904	350,287
Clients 2-5
Disaggregation of Revenue [Line Items]
Revenue	1,291,946	754,906	704,963
Clients 6-10
Disaggregation of Revenue [Line Items]
Revenue	752,325	350,865	347,832
Clients 11-25
Disaggregation of Revenue [Line Items]
Revenue	1,077,073	501,643	529,713
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 1,918,309	$ 851,970	$ 873,044

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Paragraph 40
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
-Paragraph 32
-Subparagraph (b)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Summary of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Billed services (accounts receivable)	$ 1,349,851	$ 722,420
Allowance for credit losses (note 19)	(7,081)	(7,149)	$ (7,380)
Accounts receivable (net)	1,342,770	715,271
Unbilled services (unbilled revenue)	623,121	428,684
Accounts receivable and unbilled revenue, net	1,965,891	1,143,955
Unearned revenue (payments on account)	(1,323,961)	(660,883)
Net balance	(700,840)	$ (232,199)
Change in unbilled receivables	194,437
Change in unearned revenue (payments on account)	(663,078)
Change in advance payments netted against unbilled contracts receivable	$ (468,641)
Change in unbilled receivables (in percent)	45.40%
Change in unearned revenue (payments on account) (in percent)	100.30%
Change in advance payments netted against unbilled contracts receivable (in percent)	(201.80%)

Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Amounts due to third parties for reimbursable expenses	$ 323,600	$ 138,200
Change in unbilled receivables	194,437
Change in unearned revenue (payments on account)	663,078
Increase in advance payments netted against unbilled contracts receivable	(468,641)
Bad debt expense	900	$ 2,900
Revenue, remaining performance obligation, amount	$ 13,300,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation (in percent)	48.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months

Provision for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Opening provision	$ 7,149	$ 7,380
Amounts used during the year	(116)	(2,561)
Amounts provided during the year	705	2,692
Amounts released during the year	(544)	(510)
Foreign exchange	(113)	148
Closing provision	$ 7,081	$ 7,149

Business Segment and Geographical Information - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments \| segment	1
Income from operations, excluding restructuring, transaction and integration costs	$ 607,900
Restructuring charges	31,105	$ 18,089	$ 0
Transaction and integration related (Note 6)	198,263	(759)	4,085
Income from operations	378,529	$ 391,500	$ 433,406
PRA Health Sciences, Inc
Segment Reporting Information [Line Items]
Transaction and integration related (Note 6)	198,300
2021 Restructuring Plan
Segment Reporting Information [Line Items]
Restructuring charges	$ 31,100

Business Segment and Geographical Information - Distribution of Net Revenue by Geographical Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 5,480,826	$ 2,797,288	$ 2,805,839
Ireland
Segment Reporting Information [Line Items]
Revenue	1,365,909	1,181,292	1,252,834
Rest of Europe
Segment Reporting Information [Line Items]
Revenue	1,175,515	416,884	388,916
U.S.
Segment Reporting Information [Line Items]
Revenue	2,581,007	925,563	892,497
Other
Segment Reporting Information [Line Items]
Revenue	$ 358,395	$ 273,549	$ 271,592

- Definition

+ References

+ Details

Business Segment and Geographical Information - Distribution of Income from Operations, Excluding Restructuring, by Geographical Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Income from operations, excluding restructuring and other items	$ 607,897	$ 408,830	$ 433,406
Ireland
Segment Reporting Information [Line Items]
Income from operations, excluding restructuring and other items	161,862	295,360	314,287
Rest of Europe
Segment Reporting Information [Line Items]
Income from operations, excluding restructuring and other items	183,436	35,402	37,997
U.S.
Segment Reporting Information [Line Items]
Income from operations, excluding restructuring and other items	231,971	56,921	60,272
Other
Segment Reporting Information [Line Items]
Income from operations, excluding restructuring and other items	$ 30,628	$ 21,147	$ 20,850

Business Segment and Geographical Information - Distribution of Long-lived Assets, Net, by Geographical Area (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Long-lived assets	$ 534,567	$ 258,904
Ireland
Segment Reporting Information [Line Items]
Long-lived assets	118,253	118,361
Rest of Europe
Segment Reporting Information [Line Items]
Long-lived assets	121,174	36,723
U.S.
Segment Reporting Information [Line Items]
Long-lived assets	239,828	65,152
Other
Segment Reporting Information [Line Items]
Long-lived assets	$ 55,312	$ 38,668

Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 106,205	$ 13,062	$ 13,059
Cash paid for income taxes (net of refunds)	$ 55,105	$ 27,604	$ 29,836

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Currency translation adjustments	$ (75,986)	$ (15,894)
Currency impact on long term funding	(9,854)	(9,329)
Actuarial loss on defined benefit pension plan (note 10)	(5,098)	(9,364)
Loss on interest rate hedge	0	(905)
Amortization of loss on interest rate hedge	1	15
Total	(90,937)	(35,477)
Interest Rate Contract
Accumulated Other Comprehensive Income (Loss) [Line Items]
Realized gain on interest rate hedge	0	4,658
Amortization of gain on interest rate hedge	$ 0	$ (4,658)

Operating Leases - Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease costs	$ 51,200	$ 31,088
Income from sub-leases	(1,338)	(940)
Net operating lease costs	$ 49,862	$ 30,148

Operating Leases Operating Leases - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net operating lease costs	$ 49,862,000	$ 30,148,000
Costs related to variable lease payments	0	0
Right-of-use assets obtained in exchange for lease obligations	10,200,000	12,100,000
Impairment of long lived assets	$ 15,400,000	$ 5,400,000
Weighted average remaining lease term	6 years 10 months 28 days	4 years 5 months 12 days
Weighted average discount rate (in percent)	2.51%	2.53%
Operating lease liabilities	$ 49,949,000	$ 24,334,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Other current liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities	$ 49,900,000	$ 24,300,000
Selling, general and administrative
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net operating lease costs	47,500,000	27,600,000
Direct costs
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net operating lease costs	$ 2,400,000	$ 2,500,000

Operating Leases Operating Leases - Operating Lease Maturity (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Leases [Abstract]
2022	$ 54,292
2023	45,469
2024	29,607
2025	20,758
2026	17,714
Thereafter	59,858
Total future minimum lease payments	227,698
Lease imputed interest	(18,266)
Total	$ 209,432

Non-current bank credit lines and loan facilities - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Jul. 01, 2021	Dec. 31, 2020	Dec. 08, 2020
Debt Instrument [Line Items]
Total debt	$ 5,501,213		$ 350,000
Less current portion of long-term debt	(55,150)		0
Total long-term debt	5,446,063		350,000
Less debt issuance costs and debt discount	(64,901)		(1,523)
Total long-term debt, net	$ 5,381,162		348,477
Senior Secured Credit Facility \| Term loan
Debt Instrument [Line Items]
Debt instrument, interest rate (in percent)	2.75%	1.00%
Total debt	$ 5,001,213		0
Senior Secured Notes \| Senior Secured Notes
Debt Instrument [Line Items]
Debt instrument, interest rate (in percent)	2.875%	2.875%
Total debt	$ 500,000		0
Senior Notes \| Series A notes
Debt Instrument [Line Items]
Debt instrument, interest rate (in percent)				2.32%
Total debt	0		275,000
Senior Notes \| Series B notes
Debt Instrument [Line Items]
Debt instrument, interest rate (in percent)				2.43%
Total debt	$ 0		$ 75,000

Non-current bank credit lines and loan facilities - Narrative (Details)					2 Months Ended	4 Months Ended	12 Months Ended
	Dec. 29, 2021 USD ($)	Sep. 27, 2021 USD ($)	Jul. 01, 2021 USD ($)	Dec. 08, 2020 USD ($) tranche	Dec. 31, 2021 USD ($)	Nov. 09, 2021	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Total financing costs							$ 182,423,000	$ 13,019,000	$ 13,276,000
Cash paid for interest							106,205,000	$ 13,062,000	$ 13,059,000
Issue of senior notes, number of tranches \| tranche				2
Long-term debt at fair value					$ 5,507,200,000		5,507,200,000
PRA Health Sciences, Inc
Debt Instrument [Line Items]
Total financing costs							$ 86,700,000
Term loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)					2.75%	3.00%	2.50%
Basis spread on variable rate, step down percentage (in percent)							0.25%
First lien net leverage ratio					4		4
Decrease in basis spread on variable rate					0.25%
Term loan \| London Interbank Offered Rate (LIBOR) \| Maximum
Debt Instrument [Line Items]
First lien net leverage ratio					4.00		4.00
Term loan \| London Interbank Offered Rate (LIBOR) \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							0.50%
First lien net leverage ratio					1.00		1.00
Senior secured revolving loan facility \| Variable rate component one \| Base rate
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							0.60%
Senior secured revolving loan facility \| Variable rate component one \| Base rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							1.00%
Senior secured revolving loan facility \| Variable rate component one \| Base rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							0.25%
Senior secured revolving loan facility \| Variable rate component two \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							1.60%
Senior secured revolving loan facility \| Variable rate component two \| London Interbank Offered Rate (LIBOR) \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							2.00%
Senior secured revolving loan facility \| Variable rate component two \| London Interbank Offered Rate (LIBOR) \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)							1.25%
Senior Secured Credit Facility \| Senior secured credit facility and senior secured notes
Debt Instrument [Line Items]
Debt discount paid					$ 27,600,000		$ 27,600,000
Senior Secured Credit Facility \| Term loan
Debt Instrument [Line Items]
Debt instrument, face amount			$ 5,515,000,000
Debt instrument, interest rate (in percent)			1.00%		2.75%		2.75%
Repayments of senior debt	$ 500,000,000	$ 13,800,000
Cash paid for interest	$ 40,800,000	$ 40,400,000
Payments of Debt Restructuring Costs							$ 5,600,000
Line of credit \| Senior secured revolving loan facility \| Revolving loan facility
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 300,000,000
Long-term line of credit					$ 0		0
Letter of credit \| Senior secured revolving loan facility \| Revolving loan facility
Debt Instrument [Line Items]
Letters of credit outstanding amount					$ 4,100,000		$ 4,100,000
Senior Secured Notes \| Senior Secured Notes
Debt Instrument [Line Items]
Debt instrument, face amount			$ 500,000,000
Debt instrument, interest rate (in percent)			2.875%		2.875%		2.875%
Senior Notes \| Senior Notes 2020
Debt Instrument [Line Items]
Proceeds from issuance of long-term debt				$ 350,000,000
Effective interest rate (in percent)							2.41%
Repayments of debt			$ 364,000,000
Senior Notes \| Series A notes
Debt Instrument [Line Items]
Debt instrument, face amount				$ 275,000,000
Debt instrument, interest rate (in percent)				2.32%
Senior Notes \| Series B notes
Debt Instrument [Line Items]
Debt instrument, face amount				$ 75,000,000
Debt instrument, interest rate (in percent)				2.43%

Non-current bank credit lines and loan facilities - Schedule of Finance Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Interest expense on drawn facilities	$ 93,809	$ 13,406	$ 13,659
Amortization of financing costs and debt discount	12,890	523	540
Transaction and one time financing costs	75,391	0	0
Other financing costs/(credits)	333	(910)	(923)
Total financing costs	$ 182,423	$ 13,019	$ 13,276

Non-current bank credit lines and loan facilities - Schedule of Maturities of Long-term Debt (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Debt Disclosure [Abstract]
2022	$ 55,150
2023	55,150
2024	55,150
2025	55,150
2026 and thereafter	5,280,613
Total long-term debt, net	$ 5,501,213

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References + Details

Fair value (Details) - USD ($) $ in Millions	12 Months Ended
Fair value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Increase in fair value	$ 3.2	$ 2.5
Carrying value of long-term investments in equity	22.6	$ 15.8
Fair value, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets at fair value	13,748.8
Goodwill	9,037.9
Identifiable intangible assets, net	$ 4,710.8

Impact of New Accounting Pronouncements (Details) - USD ($)	6 Months Ended
	Dec. 31, 2021	Jul. 01, 2021	Dec. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill	$ 9,037,931,000		$ 936,257,000	$ 883,170,000
Accounting Standards Update 2021-08
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill		$ 16,000,000
Contract with customer, liability		$ 16,000,000
Contract with customer, liability, revenue recognized	4,000,000
Increase (decrease) in revenue from contracts with customers	$ 0

Related Parties (Details) - USD ($)	12 Months Ended
Related Parties (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Ownership percentage	49.00%
Majority investor, ownership percentage	51.00%
Oncacare
Related Party Transaction [Line Items]
Equity method investment, aggregate cost	$ 4,900,000
Ownership percentage	49.00%
DS Biopharma Limited \| Subsidiaries
Related Party Transaction [Line Items]
Revenue earned from related parties	$ 30,000	$ 321,000
Amounts due from related parties	12,000	41,000
Afimmune Limited \| Subsidiaries
Related Party Transaction [Line Items]
Revenue earned from related parties	551,000	9,000
Amounts due from related parties	197,000	$ 0
Oncacare
Related Party Transaction [Line Items]
Amounts due from related parties	264,000
Expenses incurred from related party transactions	465,000
Loan granted tp related party	$ 10,000,000
Related party, loan interest rate	1.60%
Interest receivable, related party loans	$ 23,000

Net Income Per Ordinary Share - Reconciliation of Number of Shares Used in Computation of Basic and Diluted Net Income Per Ordinary Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Weighted average number of ordinary shares outstanding for basic net income per ordinary share (in shares)	67,110,186	52,859,911	53,859,537
Effect of dilutive share options outstanding (in shares)	958,125	423,674	473,924
Weighted average number of ordinary shares outstanding for diluted net income per ordinary share (in shares)	68,068,311	53,283,585	54,333,461

Net Income Per Ordinary Share - Reconciliation of Net Income Attributable to the Group Per the Statement of Operating Income and Net Income Used For Net Income Per Ordinary Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net income attributable to the Group	$ 153,185	$ 332,331	$ 373,986
Noncontrolling interest adjustment to redemption amount	0	(4,522)	(5,048)
Net income attributable to the Group (including NCI redemption adjustment)	$ 153,185	$ 327,809	$ 368,938
Net income per Ordinary Share attributable to the Group (including NCI redemption adjustment):
Basic (USD per share)	$ 2.28	$ 6.20	$ 6.85
Diluted (USD per share)	$ 2.25	$ 6.15	$ 6.79

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Subsequent Events (Details) - USD ($)		2 Months Ended	12 Months Ended
Subsequent Events (Details) - USD ($)	Dec. 31, 2019	Mar. 01, 2022	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 18, 2022	Oct. 03, 2016
Subsequent Event [Line Items]
Ordinary shares redeemed, value			$ 175,000,000	$ 146,931,000
Buyback program
Subsequent Event [Line Items]
Stock repurchase program, authorized amount							$ 400,000,000
Ordinary shares redeemed, value	$ 5,300,000		$ 175,000,000	$ 141,600,000	$ 372,100,000
Subsequent event \| Buyback program
Subsequent Event [Line Items]
Stock repurchase program, authorized amount						$ 100,000,000
Ordinary shares redeemed, value		$ 80,900,000