Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Harvey Keith 2. Issuer Name and Ticker or Trading Symbol KAISER ALUMINUM CORP [KALU] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) President & CEO (Last) (First) (Middle) 1550 WEST MCEWEN DRIVE, SUITE 500 3. Date of Earliest Transaction (Month/Day/Year) 03/05/2026 (Street) FRANKLIN, TN 37067 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.01 per share 03/05/2026 A 17,795(1) A $ 0 (1) 121,026(2) D Common Stock, par value $0.01 per share 03/05/2026 A 47,895(3) A $ 0 (3) 168,921(2) D Common Stock, par value $0.01 per share 03/05/2026 F(4) 17,722 D $125.84 151,199(2) D Common Stock, par value $0.01 per share 03/05/2026 F(5) 6,859 D $125.84 144,340(6) D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Harvey Keith 1550 WEST MCEWEN DRIVE SUITE 500 FRANKLIN, TN 37067	X		President & CEO

Signatures

/s/ Cherrie I. Tsai, with power of attorney for Keith Harvey		03/09/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Grant to the reporting person effective as of March 5, 2026 of restricted stock units under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan, as amended and restated. All restrictions will lapse on March 5, 2029 or earlier uponthe occurrence of certain specified circumstances.
(2)	Includes 89,994 shares acquired pursuant to grants of restricted stock units.
(3)	Shares earned upon the vesting on March 5, 2026 of certain performance shares granted to the reporting person in 2023 under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan. On March 5, 2026, the Registrant's compensation committee certified the performance shares payout multiplier based on the level of achievement by the Registrant of certain pre-established performance goals for 2023 through 2025.
(4)	Shares withheld to satisfy the withholding tax obligations resulting from the vesting on March 5, 2026 of the above-referenced performance shares.
(5)	Shares withheld to satisfy the withholding tax obligations resulting from the vesting on March 5, 2026 of certain restricted stock units granted to the reporting person in 2023 under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan.
(6)	Includes 72,565 shares acquired pursuant to grants of restricted stock units.

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