[Form 4] Kaiser Aluminum Corporation Insider Trading Activity

Rhea-AI Filing Summary

Jason Walsh, EVP - Manufacturing at Kaiser Aluminum Corporation (KALU), reported a transaction on 08/12/2025 in which 7,236 shares of common stock were disposed at $74.72 per share. The filing states these shares were withheld to satisfy withholding tax obligations from the vesting of restricted stock units granted in 2020 under the company's 2016 Equity and Incentive Compensation Plan. After the transaction, the reporting person beneficially owned 42,770 shares, which the filing notes include 14,431 shares acquired pursuant to grants of restricted stock units. The Form 4 was executed by John M. Donnan with power of attorney for Jason Walsh on 08/14/2025.

Insights

Financial Analyst

TL;DR: Insider tax-withholding sale from RSU vesting; transaction disclosed and ownership updated.

The filing documents a non-voluntary disposition of 7,236 shares at $74.72 executed to satisfy tax withholding on vested 2020 RSUs. Such withholding-based dispositions are routine and do not necessarily indicate a change in executive sentiment about the company. The report also updates beneficial ownership to 42,770 shares, explicitly noting 14,431 shares originate from RSU grants. From a capital markets perspective, this transaction is informational rather than strategically material.

Corporate Governance Expert

TL;DR: Filing meets disclosure requirements; sale tied to compensation tax obligations, not an open-market trade.

The Form 4 clearly states the disposition was to satisfy tax withholding arising from RSU vesting under the 2016 Equity and Incentive Compensation Plan. The signature by a power of attorney and the explanation line conform to standard Form 4 practices. This disclosure provides investors with clarity on the nature of the change in beneficial ownership but does not signal executive reallocation of holdings for liquidity or diversification.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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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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 for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Walsh Jason

(Last) (First) (Middle)

1550 WEST MCEWEN DRIVE

SUITE 500

(Street)

FRANKLIN TN 37067

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
KAISER ALUMINUM CORP [ KALU ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP - Manufacturing

3. Date of Earliest Transaction (Month/Day/Year)
08/12/2025

4. If Amendment, Date of 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

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	08/12/2025		F(1)		7,236	D	$74.72	42,770(2)	D

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 Securities Underlying Derivative Security (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: 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

Explanation of Responses:

1. Shares withheld to satisfy the withholding tax obligations resulting from the vesting on August 12, 2025 of certain restricted stock units granted to the reporting person in 2020 under the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan.

2. Includes 14,431 shares acquired pursuant to grants of restricted stock units.

	/s/ John M. Donnan, with power of attorney for Jason Walsh	08/14/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
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