ICON plc 2026年年度报告和过渡报告

If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. Yes☐No☒ Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for suchshorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes☒No☐Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒No☐Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or an emerging growth company. See definition of “large accelerated filer, Non-accelerated filer☐ If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section If “Other” has been checked in response to the previous question, indicate by check mark which financial statement item the registrant has elected to follow. Item 17☐Item 18☐If this is an annual report, indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act) Yes☐No☒ EXPLANATORY NOTE Overview As described in our Report on Form 6-K furnished on April 29, 2026, the Audit Committee of the Board of Directors (the “Audit Committee”), after discussion with managementof the Company, concluded on April 27, 2026, that the Company’s previously issued audited financial statements included in its Annual Reports on Form 20-F for the yearsended December31, 2024 and 2023 (the “Affected Audited Periods”) and the unaudited interim financial statements included in the Company’s Current Reports on Form 6-Kfor the quarterly periods ending on and falling between September 30, 2025 and March 31, 2023 (the “Affected Unaudited Periods” and together with the Affected AuditedPeriods, the “Restated Periods”) should no longer be relied upon. In this Annual Report on Form 20-F (this “Form 20-F”) for the year ended December31, 2025, we are restating the consolidated financial statements for the Affected AuditedPeriods, that were previously reported in our Annual Reports on Form 20-F for the years ended December31, 2024 and 2023. Accordingly, this filing includes more information than would normally be included in an Annual Report on Form 20-F in order to provide a composite presentation ofinformation for the Affected Audited Periods. In addition to the consolidated financial statements and related information for the year ended December31, 2025, this Form 20-F includes the following (collectively, the“Restatement"): •the restated Consolidated Balance Sheets at December31, 2024 and December31, 2023, and•the restated Consolidated Statements of Operations, Consolidated Statements of Comprehensive Income, Consolidated Statements of Shareholders’ Equity andConsolidated Statements of Cash Flows for the years ended December31, 2024 and 2023. For additional information, see Note 1A,Restatement of Previously Issued Consolidated Financial Statementsto the consolidated financial statements included in this Form20-F. This Form 20-F also includes additional information regarding the Affected Audited Periods, including in Item 5.Operating and Financial Review and Prospects. We intend to restate the financial statements for the Affected Unaudited Periods through an amendment to our Current Report on Form 6-K originally filed with the U.S.Securities and Exchange Commission (“SEC”) on October 23, 2025. The Company does not intend to separately amend other filings that were previously filed with the SEC. Conclusion of Investigation As previously disclosed, in October 2025, the Audit Committee initiated an investigation into certain accounting practices and controls, following concerns reported to theAudit Committee through Company management. The Audit Committee promptly engaged outside legal counsel, who were supported by forensic and technical accountingfirms, to conduct the investigation (the “Investigation”) and notified the Company’s independent registered public accounting firm. The Company has also self-reported thematter to the SEC and other relevant agencies. The Investigation primarily focused on r