St. Mary Michele T 4

What Happened
Michele St. Mary, Chief Legal Officer & General Counsel of Amentum (AMTM), had 7,080 restricted stock units (RSUs) vest on February 17, 2026. Upon vesting she was issued 7,080 shares of common stock; 2,308 of those shares were tendered/withheld to cover tax withholding at $30.05 per share, generating $69,355. The net shares delivered to her were 4,772. This was a compensation vesting event, not an open-market purchase or sale.

Key Details

• Transaction date: February 17, 2026; Form filed February 18, 2026 (filed timely).
• Award: 7,080 RSUs vested (each RSU = 1 share).
• Tax withholding: 2,308 shares withheld at $30.05/share = $69,355 (Disposition code F).
• Net shares delivered to insider: 4,772 shares.
• Transaction codes: M = exercise/conversion of derivative (conversion of RSUs to shares); F = tax withholding/tendered shares.
• Footnotes: RSUs vested on Feb 17, 2026; withheld shares represent tax withholding upon vesting.
• Shares owned after the transaction were not specified in the provided Form 4.

Context
RSU vesting is a routine form of equity compensation; withholding shares for taxes is a common administrative action and does not by itself indicate insider sentiment. This was not an open-market sale or purchase — rather a conversion of awarded RSUs into shares with a portion withheld for tax obligations.