Trinseo PLC 2025年度报告

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule405 of Regulation S-T duringthe preceding 12months (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, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule12b-2 of the Exchange Act. Largeacceleratedfiler☐Acceleratedfiler☒Non-accelerated filer☐Smallerreportingcompany☐Emerginggrowthcompany☐ 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 financialreporting under Section404(b)of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☒ If securities are registered pursuant to Section12(b)of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect thecorrection of an error to previously issued financial statements.☐Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐ Indicate by check mark whether the Company is a shell company (as defined in Rule12b-2 of the Exchange Act).Yes☐No☒As of March5, 2026, there were 36,559,868 shares of the registrant’s ordinary shares outstanding. The aggregate market value of the voting and non-voting shares of the registrant held by non-affiliates of Trinseo PLC computed by reference to the closing price of theregistrant’s common shares on the New York Stock Exchangeas ofJune30, 2025 was approximately$108,936,270.*On March23, 2026, the NYSE filed a Form25 relating to the delisting from the NYSE of our ordinary shares. The delisting became effective on March30, 2026. The ordinaryshares will continue to trade over the counter under the symbol “TSEOF.” Documents Incorporated by Reference EXPLANATORY NOTE Trinseo PLC (“Trinseo,” “we,” “us,” “our,” or the “company”) is filing this Amendment No.1 on Form10-K/A (this“Amendment”) to amend the Company’s Annual Report on Form10-K for the fiscalyear ended December31, 2025,originally filed with the Securities and Exchange Commission (the “SEC”) on March13, 2026 (the “Original Filing”). ThisAmendment is being filed to include the information required by Items 10 through 14 of PartIII of Form10-K. Wepreviously omitted this information from the Original Filing in reliance on General Instruction G(3)to Form10-K, whichpermits the information in the above-referenced items to be incorporated in the Original Filing by reference to Trinseo’sdefinitive proxy statement if such proxy statement was filed no later than 120days after our fiscalyear-end. We are filingthis Amendment to provide the information required in PartIII of Form10-K because we will not file a definitive proxystatement containing that information within 120days after the end of the fiscalyear covered by the Original Filing. This Amendment amends and restates in their entirety Items 10, 11, 12, 13 and 14 of PartIII of the Original Filing and theexhibit index set forth in PartIV of the Original Filing. The cover pageof the Original Filing is also amended to delete thereference to the incorporation by reference of Trinseo’s definitive proxy statement. Pursuant to Rule12b-15 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), this Amendmentalso contains certifications pursuant to Section302 of the Sarbanes-Oxley Act of 2002, which are attached hereto. Becauseno financial statements have been included in this Amendment and this Amendment does not contain or amend anydisclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4, and 5 of the certifications have beenomitted. Except as described above, no other portion of the Original Filing is amended hereby, and the Original Filing continues tospeak as of the filing date of the Original Filing. Accordingly, this Amendment should be read in conjunction with theOriginal Filing and Trinseo’s filings made with the SEC subsequent to the date of the Original Filing. TABLE OF CONTENTS PartIIIItem10. 3Directors, Executive Officers and Corporate Governance3Item11.Executive Compensation11Item12.Security Ownership of Certain Beneficial Owners and Management and Related Shareholder Matters31Item13.Certain Relationships and Related Transactions, and Director Independence33Item14.Principal Accounting Fees and Services34 PartIVItem15.Exhibits, Financial Statement SchedulesSignatures PartIII DIRECTORS The foll