[Form 4] Amentum Holdings, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Amentum Holdings (AMTM) reported an insider equity change by its Chief Technology Officer. On November 6, 2025, 4,838 shares of common stock were delivered upon vesting of restricted stock units. To satisfy taxes, 1,457 shares were withheld at $21.79 per share.

Following these transactions, the CTO directly owns 3,381 common shares. The filing also shows 9,678 restricted stock units remaining outstanding after the vesting event.

Insights

Equity Compensation Analyst

Routine RSU vesting; modest direct share change.

This Form 4 records equity from compensation becoming common shares. The CTO received 4,838 shares via RSU vesting on November 6, 2025, a standard conversion where each unit equals one share.

To cover withholding taxes, 1,457 shares were withheld at $21.79 per share. After these entries, direct holdings show 3,381 common shares, and 9,678 RSUs remain outstanding. These are routine administrative updates; market impact depends on future holder decisions.

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
Estimated average burden
hours per response:			0.5

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^*

Bruning Jill L

(Last) (First) (Middle)

C/O AMENTUM HOLDINGS, INC.

4800 WESTFIELDS BOULEVARD, SUITE 400

(Street)

CHANTILLY VA 20151

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Amentum Holdings, Inc. [ AMTM ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Technology Officer

3. Date of Earliest Transaction (Month/Day/Year)
11/06/2025

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	11/06/2025		M		4,838	A	(1)	4,838	D
Common Stock	11/06/2025		F		1,457(2)	D	$21.79	3,381	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
Restricted Stock Units	(3)	11/06/2025		M(1)			4,838	(4)	(4)	Common Stock	4,838	$0	9,678	D

Explanation of Responses:

1. Represents distribution of AMTM common stock upon vesting of restricted stock units.

2. Represents number of shares of AMTM common stock tendered for tax withholding upon vesting of restricted stock units.

3. Each restricted stock unit represents a contingent right to receive one share of AMTM common stock.

4. The restricted stock units awarded vested on November 6, 2025.

Remarks:

	/s/ Mark Esposito, Attorney-in-Fact	11/10/2025
	** 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 insider transaction did Amentum (AMTM) report?

The CTO reported RSU vesting delivering 4,838 AMTM common shares on November 6, 2025.

How many AMTM shares were withheld for taxes in this Form 4?

1,457 shares were withheld at $21.79 per share to satisfy tax withholding.

What are the CTO's direct AMTM share holdings after the transaction?

Direct beneficial ownership is 3,381 AMTM common shares following the reported transactions.

How many restricted stock units remain for the CTO after vesting?

9,678 AMTM restricted stock units remain outstanding after the vesting event.

What does Transaction Code M and F mean in AMTM's Form 4?

Code M indicates RSU conversion to common stock; Code F indicates shares withheld for taxes.