Sean Thomas Mullen - 17 Dec 2025 Form 4 Insider Report for Amentum Holdings, Inc. (AMTM)

Role
Chief Growth Officer
Signature
/s/ Mark Esposito, Attorney-in-Fact
Issuer symbol
AMTM
Transactions as of
17 Dec 2025
Net transactions value
-$120,242
Form type
4
Filing time
19 Dec 2025, 16:19:04 UTC
Previous filing
19 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Mullen Sean Thomas Chief Growth Officer C/O AMENTUM HOLDINGS, INC., 4800 WESTFIELDS BOULEVARD, SUITE 400, CHANTILLY /s/ Mark Esposito, Attorney-in-Fact 19 Dec 2025 0002034388

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction AMTM Common Stock Options Exercise +9,298 +44% 30,332 17 Dec 2025 Direct F1
transaction AMTM Common Stock Tax liability $120,242 -4,194 -14% $28.67 26,138 17 Dec 2025 Direct F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction AMTM Restricted Stock Units Options Exercise $0 -9,298 -100% $0.000000 0 17 Dec 2025 Common Stock 9,298 Direct F1, F3, F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Represents distribution of AMTM common stock upon vesting of restricted stock units.
F2 Represents number of shares of AMTM common stock tendered for tax withholding upon vesting of restricted stock units.
F3 Each restricted stock unit represents a contingent right to receive one share of AMTM common stock.
F4 The restricted stock units awarded vested on December 17, 2025.