凯撒铝业 2025年度报告

☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the fiscal year ended December 31, 2025 ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 KAISER ALUMINUM CORPORATION(Exact name of registrant as specified in its charter) 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 (orfor such shorter 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 thischapter) 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, a smaller reporting company, or an emerging growth company. See thedefinitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act: If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accountingstandards 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 underSection 404(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 Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of anerror 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’sexecutive officers during the relevant recovery period pursuant to §240.10D-1(b).☐ Documents Incorporated by Reference. Certain portions of the registrant’s definitive proxy statement related to the registrant’s 2026 annual meeting of stockholders are incorporated byreference into Part III of this Annual Report on Form 10-K. COMMONLY USED OR DEFINED TERMS TABLE OF CONTENTS PART I Item 1.BusinessItem 1A.Risk FactorsItem 1B.Unresolved Staff CommentsItem 1C.CybersecurityItem 2.PropertiesItem 3.Legal ProceedingsItem 4.Mine Safety Disclosures PART II Item 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities28Item 6.[Reserved]29Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations30Item 7A.Quantitative and Qualitative Disclosures About Market Risk39Item 8.Financial Statements and Supplementary Data41Item 9.Changes in and Disagreements with Accountants on Accounting and Financial Disclosure85Item 9A.Controls and Procedures85Item 9B.Other Information85Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspection85 PART III Item 10.Directors, Executive Officers and Corporate Governance86Item 11.Executive Compensation86Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters86Item 13.Certain Relationships and Related Transactions and Director Independence86Item 14.Principal Accountant Fees and Services86 PART IV Item 15.Exhibits and Financial Statement Schedules87Item 16.Form 10-K Summary90 SIGNATURES PART I Forward-Looking Statements This Annual Report on Form 10-K contains statements which constitute “forward-looking statements” within the meaning ofthe Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended and Section 21E of theSecurities Exchange Act of 1934, as amended, as applicable. These statements appear throughout this Form 10-K, including Item 1.“Business – Business Operations,” Item 1A. “Risk Factors” and Item 7. “Management’s Discussion and Analysis of FinancialCondition and Results of Operations.” These forward-looking statements can be identified by the use of forward-lookingterminology such as “believes,” “expects,” “may,” “estimates,” “will,” “should,” “plans” or “anticipates,” or the negative of theforegoing or other variations or comparable terminology, or by discussions of strategy. Readers are cautioned that any such forward-looking statements are not guarantees of future performance and involvesignificant risks and uncertainties and that actual results may vary from those in the forward-looking