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

Rhea-AI Filing Summary

Amentum Holdings, Inc. (AMTM) reported an equity grant to its Chief Legal Officer and General Counsel on a Form 4. On November 17, 2025, the officer acquired 22,271 shares of common stock in the form of restricted stock units at a stated price of $0, increasing the amount of securities beneficially owned to 22,271 shares held directly.

According to the filing, these restricted stock units will vest in three equal installments, with one-third vesting on each of the first, second and third anniversaries of November 17, 2025. This transaction reflects routine equity-based compensation for a senior executive rather than an open-market purchase or sale.

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^*

St. Mary Michele T

(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 Legal Officer & GC

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		22,271(1)	A	$0	22,271	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 insider transaction did Amentum Holdings (AMTM) report on this Form 4?

The company reported that its Chief Legal Officer and General Counsel acquired 22,271 shares of Amentum Holdings, Inc. common stock in the form of restricted stock units on November 17, 2025.

At what price were the Amentum (AMTM) restricted stock units granted?

The restricted stock units were reported as acquired at a price of $0 per share, consistent with an equity compensation award rather than a market purchase.

How many Amentum (AMTM) shares does the reporting person beneficially own after this transaction?

Following the reported transaction, the officer beneficially owns 22,271 shares of Amentum Holdings, Inc. common stock, held in direct ownership.

What is the vesting schedule for the Amentum (AMTM) restricted stock units?

The filing states that one-third of the restricted stock units will vest on each of the first, second and third anniversaries of November 17, 2025.

Who is the insider involved in this Amentum Holdings (AMTM) Form 4 filing and what is their role?

The insider is an officer of Amentum Holdings, Inc. serving as Chief Legal Officer & General Counsel, as disclosed in the relationship section of the Form 4.

Is this Amentum (AMTM) transaction a purchase or a sale of existing shares?

The transaction is coded as an acquisition (A) of restricted stock units, indicating an award of equity compensation rather than a sale of existing shares.