克利尔沃特纸业 2025年度报告

FORM 11-K ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACTOF 1934 For the fiscal year ended December31, 2025OR TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGEACT OF 1934 For the transition period fromto A.Full title of the plan and the address of the plan, if different from that of the issuer named below: Clearwater Paper 401(k) Plan B.Name of issuer of the securities held pursuant to the plan and the address of its principal executive office: CLEARWATER PAPER CORPORATION601 West Riverside Avenue, Suite 300Spokane, Washington 99201 CLEARWATER PAPER 401(k)PLAN Financial Statements and Supplemental Schedule CLEARWATER PAPER 401(k)PLAN Table of Contents Statements of Net Assets Available for Benefits2 Statements of Changes in Net Assets Available for Benefits3 ScheduleH, Part IV, Line4(i) – Schedule of Assets (Held at End of Year)11 Exhibit Index12 Signature13 Report of Independent Registered Public Accounting Firm To the Benefits Committee of theClearwater Paper 401(k) Plan Opinion on the Financial Statements We have audited the accompanying statements of net assets available for benefits of the Clearwater Paper 401(k) Plan(the “Plan”) as of December 31, 2025 and 2024, the related statements of changes in net assets available for benefits forthe years then ended, and the related notes (collectively referred to as thefinancial statements). In our opinion, the Basis for Opinion These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion onthe Plan’s financial statements based on our audits. We are a public accounting firm registered with the Public CompanyAccounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Plan in We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan andperformthe audits to obtain reasonable assurance about whether the financial statements are free of materialmisstatement, whether due to error or fraud. The Plan is not required to have, nor were we engaged to perform, an auditof its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal Our audits included performing procedures to assess the risks of material misstatement of the financial statements,whether due to error or fraud, and performing procedures that respond to those risks. Such procedures includedexamining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also Supplemental Information The supplemental information in the accompanying schedule of assets (held at end of year) as of December 31, 2025, hasbeen subjected to audit procedures performed in conjunction with the audit of the Plan’s financial statements. Thesupplemental information is the responsibility of the Plan’s management. Our audit procedures included determiningwhether the supplemental information reconciles to the financial statements or the underlying accounting and other /s/ LBMC, PC We have served as the Plan’s auditor since 2023.Knoxville, TennesseeJune25, 2026 CLEARWATER PAPER 401(k) PLAN Statements of Net Assets Available for Benefits CLEARWATER PAPER 401(k) PLAN Notes to Financial Statements Years endedDecember31, 2025 and 2024 (1) Description of Plan The following is a general description of the Clearwater Paper 401(k) Plan (the "Plan"). This description applies toeach of the years for which financial statements are presented and provides only general information. For a more (a)General The Plan is a defined contribution plan. The Plan is subject to the applicable provisions of the EmployeeRetirement Income Security Act of 1974, as amended (ERISA). The Plan was restated effective January 1, On May 1, 2024, Clearwater Paper Corporation (Clearwater Paper) acquired a paperboard mill and associatedfacilities, located in Augusta, Georgia from Graphic Packaging International, LLC. In connection therewith, On November 1, 2024, Clearwater Paper completed the sale of its tissue business to Sofidel America Corp. Asa result of the divestiture, approximately 1,260 participants in the Plan were terminated. Affected participantswere fully vested in their account balances and were given the opportunity to rollover their account balances to (b)Plan Sponsor and Administration Clearwater Paper sponsors the Plan. The Plan is administered by the Clearwater Paper Benefits Committee.Plan assets are held in trust by the Plan's trustee and recordkeeper. During the years ended December31,2025 and 2024, Fidelity Management Trust Company and Fidelity Workplace Services LLC (collectively, (c)Eligibility and Contributions All eligible full-time regular status salaried and non-represented hourly employees (as defined in the Plan) areeligible for participation in the Plan following 30 days of employment with Clearwater P