KAISER ALUMINUM CORP

Evaluation of Disclosure Controls and Procedures. We have established disclosure controls and procedures to ensure that the information to be disclosed by the Company in the reports that it files or submits under the Securities Exchange Act of 1934 is recorded, processed, summarized and reported within the time periods specified in SEC rules and forms and that such information is accumulated and made known to the officers who certify the Company’s financial reports and to other members of senior management and the Board of Directors as appropriate to allow timely decisions regarding required disclosure.

Based on their evaluation as of December 31, 2025, the principal executive officer and principal financial officer of the Company have concluded that the Company’s disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934) were effective.

Management’s Annual Report on Internal Control Over Financial Reporting. Management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rule 13a-15(f) under the Securities Exchange Act of 1934. Management assessed the effectiveness of our internal control over financial reporting as of December 31, 2025 using the criteria set forth in Internal Control – Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission as established in 2013. Based on management’s assessment, management concluded that our internal control over financial reporting was effective as of December 31, 2025.

Deloitte & Touche LLP, the independent registered public accounting firm that audited our consolidated financial statements for the year ended December 31, 2025 included in Item 8. “Financial Statements and Supplementary Data” of this Form 10-K, has issued an attestation report on the effectiveness of our internal control over financial reporting.

Changes in Internal Control Over Financial Reporting. There have been no changes in our internal control over financial reporting during our most recently completed fiscal quarter that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.