欧林 2025年度报告

(Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACTOF 1934 For the fiscal year ended December31, 2025 OR ☐TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGEACT OF 1934 For the transition period from ________ to ________ Commission file number 1-1070 A. Full title of the plan and the address of the plan, if different from that of the issuer namedbelow: Olin Corporation Retirement Savings Plan B. Name of issuer of the securities held pursuant to the plan and the address of its principalexecutive office: Olin Corporation190 Carondelet Plaza, Suite 1530Clayton, MO 63105 Financial Statements:Statements of Net Assets Available for Benefits3Statements of Changes in Net Assets Available for Benefits4Notes to Financial Statements5 Supplemental Information:Schedule H, Line 4i — Schedule of Assets (Held at End of Year)16 Exhibits17 Report of Independent Registered Public Accounting Firm Audit Committee, Investment Committee, Plan Administrator, Plan Management and Plan ParticipantsOlin Corporation Retirement Savings PlanClayton, Missouri Opinion on the Financial Statements Wehave audited the accompanying statements of net assets available for benefits of OlinCorporation Retirement Savings Plan (“Plan”) as of December31, 2025 and 2024, the relatedstatements of changes in net assets available for benefits for the years then ended, and the relatednotes (collectively referred to as the “financial statements”). In our opinion, the financial statementsreferred to above present fairly, in all material respects, the net assets available for benefits of thePlan as of December31, 2025 and 2024, and the changes in net assets available for benefits for theyears then ended in conformity with accounting principles generally accepted in the United States ofAmerica. Basis of Opinion These financial statements are the responsibility of the Plan’s management. Our responsibility is toexpress an opinion on these financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board(United States) (“PCAOB”) and are required to be independent with respect to the Plan in accordancewith the U.S. federal securities laws and the applicable rules and regulations of the Securities andExchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards requirethat we plan and perform the audits to obtain reasonable assurance about whether the financialstatements are free of material misstatement, whether due to error or fraud. The Plan is not requiredto have, nor were we engaged to perform, an audit of its internal control over financial reporting. Aspart of our audits, we are required to obtain an understanding of internal control over financialreporting but not for the purpose of expressing an opinion on the effectiveness of the Plan’s internalcontrol over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of thefinancial statements, whether due to error or fraud, and performing procedures that respond to thoserisks. Such procedures included examining, on a test basis, evidence regarding the amounts anddisclosures in the financial statements. Our audits also included evaluating the accounting principlesused and significant estimates made by management, as well as evaluating the overall presentationof the financial statements. We believe that our audits provide a reasonable basis for our opinion. Table of Contents Report on Supplemental Information The supplemental information in the accompanying Schedule of Assets (Held at End of Year) as ofDecember31, 2025 has been subjected to audit procedures performed in conjunction with the auditof the Plan’s financial statements. The supplemental information is the responsibility of the Plan’smanagement. Our audit procedures included determining whether the supplemental informationreconciles to the financial statements or the underlying accounting and other records, as applicable,and performing procedures to test the completeness and accuracy of the information presented in thesupplemental information. In forming our opinion on the supplemental information, we evaluatedwhether the supplemental information, including its form and content, is presented in conformity withthe Department of Labor’s Rules and Regulations for Reporting and Disclosure under theEmployeeRetirement Income Security Act of 1974. In our opinion, the Schedule of Assets (Held at End of Year)is fairly stated, in all material respects, in relation to the basic financial statements taken as a whole. /s/ Forvis Mazars, LLP We have served as the Plan’s auditor since 2025. St. Louis, MissouriJune24, 2026 Olin Corporation Retirement Savings PlanStatements of Net Assets Available for Benefits Olin Corporation Retirement Savings PlanStatements of Changes