{"transactions":[{"id":897522,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":65948,"kind":"person","name":"St. Mary Michele T","position":1,"cik":"0002057553","reported_name":"St. Mary Michele T","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Legal Officer & GC"}}],"security":"Restricted Stock Units","published_at":"2026-02-18T17:30:14.000Z","date":"2026-02-17","kind":"exercise","planned":false,"acquired":false,"shares":7080,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents distribution of AMTM common stock upon vesting of restricted stock units."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The restricted stock units awarded vested on February 17, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on February 17, 2026."}],"balance_after":14162,"derivative":{"underlying":"Common Stock","underlying_shares":7080},"source":{"system":"sec-edgar","filing":"0001628280-26-009269","document":"wk-form4_1771453809.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2057553/000162828026009269/wk-form4_1771453809.xml","form_type":"4"}},{"id":897521,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":65948,"kind":"person","name":"St. Mary Michele T","position":1,"cik":"0002057553","reported_name":"St. Mary Michele T","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Legal Officer & GC"}}],"security":"Common Stock","published_at":"2026-02-18T17:30:14.000Z","date":"2026-02-17","kind":"tax_withholding","planned":false,"acquired":false,"shares":2308,"price":30.05,"value":69355.4,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"Represents number of shares of AMTM common stock tendered for tax withholding upon vesting of restricted stock units."}],"balance_after":27043,"source":{"system":"sec-edgar","filing":"0001628280-26-009269","document":"wk-form4_1771453809.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2057553/000162828026009269/wk-form4_1771453809.xml","form_type":"4"}},{"id":897520,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":65948,"kind":"person","name":"St. Mary Michele T","position":1,"cik":"0002057553","reported_name":"St. Mary Michele T","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Legal Officer & GC"}}],"security":"Common Stock","published_at":"2026-02-18T17:30:14.000Z","date":"2026-02-17","kind":"exercise","planned":false,"acquired":true,"shares":7080,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents distribution of AMTM common stock upon vesting of restricted stock units."}],"balance_after":29351,"source":{"system":"sec-edgar","filing":"0001628280-26-009269","document":"wk-form4_1771453809.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2057553/000162828026009269/wk-form4_1771453809.xml","form_type":"4"}},{"id":994242,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":65948,"kind":"person","name":"St. Mary Michele T","position":1,"cik":"0002057553","reported_name":"St. Mary Michele T","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Legal Officer & GC"}}],"security":"Common Stock","published_at":"2025-11-19T17:40:07.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":22271,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"One-third of the restricted stock units shall vest on each of the first, second and third anniversaries of November 17, 2025."}],"balance_after":22271,"source":{"system":"sec-edgar","filing":"0001628280-25-053272","document":"wk-form4_1763592004.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2057553/000162828025053272/wk-form4_1763592004.xml","form_type":"4"}},{"id":1197421,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":65948,"kind":"person","name":"St. Mary Michele T","position":1,"cik":"0002057553","reported_name":"St. Mary Michele T","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Legal Officer & GC"}}],"security":"Restricted Stock Units","published_at":"2025-03-19T16:37:38.000Z","date":"2025-03-17","kind":"grant","planned":false,"acquired":true,"shares":21242,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"One-third of the restricted stock units shall vest on each of the first, second and third anniversaries of February 17, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"One-third of the restricted stock units shall vest on each of the first, second and third anniversaries of February 17, 2025."}],"balance_after":21242,"derivative":{"underlying":"Common Stock","underlying_shares":21242},"source":{"system":"sec-edgar","filing":"0002011286-25-000096","document":"wk-form4_1742416634.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2057553/000201128625000096/wk-form4_1742416634.xml","form_type":"4"}}]}