Mary Michele T. St. - 17 Feb 2026 Form 4 Insider Report for Amentum Holdings, Inc. (AMTM)

Role
Chief Legal Officer & GC
Signature
/s/ Indira Lall, Attorney-in-fact
Issuer symbol
AMTM
Transactions as of
17 Feb 2026
Net transactions value
-$69,355
Form type
4
Filing time
18 Feb 2026, 17:30:14 UTC
Previous filing
19 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
St. Mary Michele T Chief Legal Officer & GC C/O AMENTUM HOLDINGS, INC., 4800 WESTFIELDS BOULEVARD, SUITE 400, CHANTILLY /s/ Indira Lall, Attorney-in-fact 18 Feb 2026 0002057553

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction AMTM Common Stock Options Exercise +7,080 +32% 29,351 17 Feb 2026 Direct F1
transaction AMTM Common Stock Tax liability $69,355 -2,308 -7.9% $30.05 27,043 17 Feb 2026 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 -7,080 -33% $0.000000 14,162 17 Feb 2026 Common Stock 7,080 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 February 17, 2026.