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

Rhea-AI Filing Summary

Amentum Holdings, Inc. (AMTM)November 17, 2025, the officer acquired 17,817 shares of common stock at a price of $0, reflecting a grant of restricted stock units rather than an open-market purchase.

Following this grant, the officer beneficially owns 21,034 shares of Amentum common stock in direct ownership. The award vests over time: one-third of the restricted stock units will vest on each of the first, second and third anniversaries of November 17, 2025, creating a three-year vesting schedule tied to continued service.

11/19/2025 - 05:53 PM

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^*

Mullen Sean Thomas

(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 Growth Officer

3. Date of Earliest Transaction (Month/Day/Year)
11/17/2025

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	11/17/2025		A		17,817(1)	A	$0	21,034	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. One-third of the restricted stock units shall vest on each of the first, second and third anniversaries of November 17, 2025.

Remarks:

	/s/ Mark Esposito, Attorney-in-Fact	11/19/2025
	** 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 did Amentum Holdings (AMTM) disclose in this Form 4?

Amentum Holdings (AMTM) disclosed that its Chief Growth Officer received an equity award of 17,817 shares of common stock in the form of restricted stock units.

How many Amentum (AMTM) shares does the officer own after this transaction?

After the reported grant, the Chief Growth Officer beneficially owns 21,034 shares of Amentum common stock in direct ownership.

What was the transaction price for the Amentum (AMTM) equity grant?

The equity award was granted at a price of $0 per share, consistent with a restricted stock unit grant rather than a market purchase.

How do the Amentum (AMTM) restricted stock units vest?

One-third of the restricted stock units vest on each of the first, second and third anniversaries of November 17, 2025, creating a three-year vesting schedule.

What role does the reporting person hold at Amentum Holdings (AMTM)?

The reporting person is an officer of Amentum Holdings, Inc., serving as the company’s Chief Growth Officer.

Is this Amentum (AMTM) Form 4 filed by one or multiple reporting persons?

The Form 4 is indicated as being filed by one reporting person, not a group filing.