<div id="readability-page-1"><div>Mullen Sean Thomas Officer of Amentum Holdings Inc [AMTM] filed a Form 4 on December 19, 2025 with the Securities and Exchange Commission disclosing the following changes in ownership:<div><table><tbody><tr><th>Date</th><th>Transaction</th><th>Shares</th><th>Price</th><th>Value</th></tr><tr><td>12/17/25</td><td>Exercise</td><td>9,298</td><td>$0.00</td><td>N/A</td></tr><tr><td>12/17/25</td><td>Surrender(1)</td><td>4,194</td><td>$28.67</td><td>$120,242</td></tr></tbody></table></div>Ending Holdings: 26,138 - Direct<ul><li>(1)</li><li>Surrender of shares back to company to pay option exercise cost and/or resulting tax liability.</li></ul>For a free trial, or to learn more about our insider trading analysis and data services, please visit http://www.washingtonservice.com or contact us at (301) 913-5100 or send an email to info@washingtonservice.com.Founded in 1970, The Washington Service provides securities professionals with financial, economic and public policy research and data. </div></div>

AMTM

Officer Sean Thomas Mullen of Amentum Holdings Inc filed a Form 4 with the SEC, disclosing changes in ownership. On December 17, 2025, he exercised 9,298 shares and surrendered 4,194 shares at $28.67 each to cover option exercise costs and tax liabilities. His ending holdings are 26,138 shares directly. The Washington Service offers insider trading analysis and data services.

Officer Mullen Acquires 5,104 Of Amentum Holdings Inc [AMTM]