[Form 4] Kaiser Aluminum Corporation Insider Trading Activity

Rhea-AI Filing Summary

Tiffany Blain, listed as an officer (EVP - Sales & Marketing), reported a Section 16 transaction for Kaiser Aluminum Corporation (KALU) on 08/12/2025. The filing shows 6,982 shares were disposed at a price of $74.72 per share; the disposition is identified as F(1), and the explanation states these shares were withheld to satisfy withholding tax obligations arising from the vesting of restricted stock units granted in 2020.

After the transaction, the reporting person beneficially owned 34,931 shares (direct). The filing also notes that the total includes 11,044 shares acquired pursuant to grants of restricted stock units. The Form 4 was signed by a power of attorney on behalf of Tiffany Blain on 08/14/2025.

Positive

• Continued ownership of 34,931 shares after the transaction, maintaining insider alignment with shareholders
• Clarity on disposition: Form states shares were withheld for tax obligations from RSU vesting, indicating a routine, non-discretionary action

Negative

• Reduction of direct holdings by 6,982 shares due to withholding at $74.72 per share
• Significant portion (11,044 shares) of current holdings derived from RSU grants, which may dilute the proportion of long-term purchased shares

Insights

Securities Analyst

TL;DR Insider tax-withholding on vested RSUs led to a small, routine disposition of 6,982 shares at $74.72.

This Form 4 documents a non-discretionary, tax-related disposition: shares withheld to satisfy tax on RSU vesting. The transaction code F(1) and the explanation confirm this was not an open-market sale but a vesting-related withholding. The remaining direct ownership of 34,931 shares includes 11,044 RSU-derived shares, indicating continuing equity alignment with the company. For investors, this is a routine insider filing reflecting compensation mechanics rather than a change in strategic ownership.

Corporate Governance Expert

TL;DR Filing reflects standard executive compensation vesting and tax withholding; no governance red flags evident.

The disclosure is clear that the disposition stems from vesting of 2020 RSUs and related tax withholding, a common practice that reduces share count without implying a voluntary divestiture. The use of a power of attorney for signature is routine for timely Form 4 filings. There is no indication of unusual timing or related-party transactions in the filing text provided.

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

OMB APPROVAL

OMB Number:			3235-0287
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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^*

Tiffany Blain

(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 - Sales & Marketing

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)		6,982	D	$74.72	34,931(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 11,044 shares acquired pursuant to grants of restricted stock units.

	/s/ John M. Donnan, with power of attorney for Blain Tiffany	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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transaction did Tiffany Blain report on Form 4 for KALU?

The Form 4 reports a disposition of 6,982 common shares on 08/12/2025 at a price of $74.72 per share; the shares were withheld to satisfy tax obligations from RSU vesting.

How many shares does the reporting person own after the reported transaction?

The reporting person beneficially owned 34,931 shares (direct) following the reported transaction.

Why were shares disposed according to the filing?

The filing explains the shares were withheld to satisfy withholding tax obligations resulting from the vesting of restricted stock units granted in 2020.

How many shares were acquired from RSU grants as noted in the Form 4?

The filing notes that 11,044 shares are included that were acquired pursuant to grants of restricted stock units.

Who signed the Form 4 and when was it signed?

The Form 4 was signed by John M. Donnan with power of attorney for Tiffany Blain on 08/14/2025.