{"transactions":[{"id":4622537,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":67069,"kind":"person","name":"Thompson Christopher M.T.","position":1,"cik":"0001483410","reported_name":"Thompson Christopher M.T.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-09-18T01:35:55.000Z","date":"2026-08-14","kind":"gift","planned":false,"acquired":false,"shares":4250,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Trust"},"footnotes":[{"field":"date","element":"transactionDate","label":"F1","text":"Mr. Thompson's filing was late due to an administrative oversight."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"On August 14, 2026, the reporting person transferred an LLC interest representing 4,250 shares of AMTM common stock to an immediate family for no consideration."}],"balance_after":5750,"source":{"system":"sec-edgar","filing":"0001483410-26-000005","document":"wk-form4_1789695352.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000148341026000005/wk-form4_1789695352.xml","form_type":"4"}},{"id":788632,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Restricted Stock Units","published_at":"2026-05-07T20:32:28.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":false,"shares":18145,"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":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."}],"balance_after":18146,"derivative":{"underlying":"Common Stock","underlying_shares":18145},"source":{"system":"sec-edgar","filing":"0002011286-26-000021","document":"wk-form4_1778185946.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000021/wk-form4_1778185946.xml","form_type":"4"}},{"id":788631,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:32:28.000Z","date":"2026-05-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":8184,"price":24.89,"value":203699.76,"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":376019,"source":{"system":"sec-edgar","filing":"0002011286-26-000021","document":"wk-form4_1778185946.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000021/wk-form4_1778185946.xml","form_type":"4"}},{"id":788630,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:32:28.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":true,"shares":18145,"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":384203,"source":{"system":"sec-edgar","filing":"0002011286-26-000021","document":"wk-form4_1778185946.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000021/wk-form4_1778185946.xml","form_type":"4"}},{"id":788662,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Restricted Stock Units","published_at":"2026-05-07T20:31:49.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":false,"shares":9072,"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":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."}],"balance_after":9073,"derivative":{"underlying":"Common Stock","underlying_shares":9072},"source":{"system":"sec-edgar","filing":"0002011286-26-000020","document":"wk-form4_1778185904.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000201128626000020/wk-form4_1778185904.xml","form_type":"4"}},{"id":788661,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:31:49.000Z","date":"2026-05-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":2762,"price":24.89,"value":68746.18,"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."}],"balance_after":32448,"source":{"system":"sec-edgar","filing":"0002011286-26-000020","document":"wk-form4_1778185904.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000201128626000020/wk-form4_1778185904.xml","form_type":"4"}},{"id":788660,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:31:49.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":true,"shares":9072,"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":35210,"source":{"system":"sec-edgar","filing":"0002011286-26-000020","document":"wk-form4_1778185904.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000201128626000020/wk-form4_1778185904.xml","form_type":"4"}},{"id":788629,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2026-05-07T20:31:16.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":false,"shares":13609,"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":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."}],"balance_after":13609,"derivative":{"underlying":"Common Stock","underlying_shares":13609},"source":{"system":"sec-edgar","filing":"0002011286-26-000019","document":"wk-form4_1778185869.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000019/wk-form4_1778185869.xml","form_type":"4"}},{"id":788628,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:31:16.000Z","date":"2026-05-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":4097,"price":24.89,"value":101974.33,"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":118187,"source":{"system":"sec-edgar","filing":"0002011286-26-000019","document":"wk-form4_1778185869.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000019/wk-form4_1778185869.xml","form_type":"4"}},{"id":788627,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:31:16.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":true,"shares":13609,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents a distribution of AMTM common stock upon vesting of restricted stock units."}],"balance_after":122284,"source":{"system":"sec-edgar","filing":"0002011286-26-000019","document":"wk-form4_1778185869.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000019/wk-form4_1778185869.xml","form_type":"4"}},{"id":788670,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Restricted Stock Units","published_at":"2026-05-07T20:30:21.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":false,"shares":9072,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."}],"balance_after":9073,"derivative":{"underlying":"Common Stock","underlying_shares":9072},"source":{"system":"sec-edgar","filing":"0002011286-26-000018","document":"wk-form4_1778185803.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000201128626000018/wk-form4_1778185803.xml","form_type":"4"}},{"id":788669,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:30:21.000Z","date":"2026-05-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":2731,"price":24.89,"value":67974.59,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"Represents number of shares of AMTM common stock tendered for tax withholding upon vesting of restricted stock units."}],"balance_after":197457,"source":{"system":"sec-edgar","filing":"0002011286-26-000018","document":"wk-form4_1778185803.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000201128626000018/wk-form4_1778185803.xml","form_type":"4"}},{"id":788668,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:30:21.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":true,"shares":9072,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents distribution of AMTM common stock upon vesting of restricted stock units."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Includes 117 shares acquired under the employee stock purchase plan in March  2026."}],"balance_after":200188,"source":{"system":"sec-edgar","filing":"0002011286-26-000018","document":"wk-form4_1778185803.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000201128626000018/wk-form4_1778185803.xml","form_type":"4"}},{"id":788625,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2026-05-07T20:29:07.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":false,"shares":13609,"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":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"One-half of the restricted stock units shall vest and be delivered on the 18th month and three-year anniversaries of the date of grant."}],"balance_after":13609,"derivative":{"underlying":"Common Stock","underlying_shares":13609},"source":{"system":"sec-edgar","filing":"0002011286-26-000017","document":"wk-form4_1778185745.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000017/wk-form4_1778185745.xml","form_type":"4"}},{"id":788624,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:29:07.000Z","date":"2026-05-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":3314,"price":24.89,"value":82485.46,"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":106652,"source":{"system":"sec-edgar","filing":"0002011286-26-000017","document":"wk-form4_1778185745.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000017/wk-form4_1778185745.xml","form_type":"4"}},{"id":788623,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2026-05-07T20:29:07.000Z","date":"2026-05-06","kind":"exercise","planned":false,"acquired":true,"shares":13609,"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":109966,"source":{"system":"sec-edgar","filing":"0002011286-26-000017","document":"wk-form4_1778185745.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128626000017/wk-form4_1778185745.xml","form_type":"4"}},{"id":859023,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2026-03-05T21:06:30.000Z","date":"2026-03-04","kind":"gift","planned":false,"acquired":false,"shares":30000,"price":0,"value":0.0,"ownership":{"direct":true},"balance_after":190999,"source":{"system":"sec-edgar","filing":"0001628280-26-015158","document":"wk-form4_1772744785.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000162828026015158/wk-form4_1772744785.xml","form_type":"4"}},{"id":862223,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2026-03-04T21:12:14.000Z","date":"2026-03-02","kind":"exercise","planned":false,"acquired":false,"shares":2808,"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":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The restricted stock units awarded vested on March 2, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on March 2, 2026."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":2808},"source":{"system":"sec-edgar","filing":"0001628280-26-014626","document":"wk-form4_1772658730.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026014626/wk-form4_1772658730.xml","form_type":"4"}},{"id":862222,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2026-03-04T21:12:14.000Z","date":"2026-03-02","kind":"tax_withholding","planned":false,"acquired":false,"shares":750,"price":30.7,"value":23025.0,"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":96357,"source":{"system":"sec-edgar","filing":"0001628280-26-014626","document":"wk-form4_1772658730.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026014626/wk-form4_1772658730.xml","form_type":"4"}},{"id":862221,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2026-03-04T21:12:14.000Z","date":"2026-03-02","kind":"exercise","planned":false,"acquired":true,"shares":2808,"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":97107,"source":{"system":"sec-edgar","filing":"0001628280-26-014626","document":"wk-form4_1772658730.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026014626/wk-form4_1772658730.xml","form_type":"4"}},{"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":912378,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":15111,"kind":"person","name":"IRELAND SUSAN LESLIE","position":1,"cik":"0001718953","reported_name":"IRELAND SUSAN LESLIE","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:11:56.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":8509,"source":{"system":"sec-edgar","filing":"0001628280-26-006839","document":"wk-form4_1770757912.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006839/wk-form4_1770757912.xml","form_type":"4"}},{"id":912377,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49517,"kind":"person","name":"Rowland Sandra E.","position":1,"cik":"0001629360","reported_name":"Rowland Sandra E.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2026-02-10T21:11:22.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":false,"shares":11564,"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":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The restricted stock units awarded vested on February 6, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on February 6, 2026."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0001628280-26-006837","document":"wk-form4_1770757878.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006837/wk-form4_1770757878.xml","form_type":"4"}},{"id":912376,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49517,"kind":"person","name":"Rowland Sandra E.","position":1,"cik":"0001629360","reported_name":"Rowland Sandra E.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:11:22.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":20073,"source":{"system":"sec-edgar","filing":"0001628280-26-006837","document":"wk-form4_1770757878.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006837/wk-form4_1770757878.xml","form_type":"4"}},{"id":912375,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49517,"kind":"person","name":"Rowland Sandra E.","position":1,"cik":"0001629360","reported_name":"Rowland Sandra E.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:11:22.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":true,"shares":11564,"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":15011,"source":{"system":"sec-edgar","filing":"0001628280-26-006837","document":"wk-form4_1770757878.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006837/wk-form4_1770757878.xml","form_type":"4"}},{"id":912374,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":45266,"kind":"person","name":"Brooks Vincent K","position":1,"cik":"0001809046","reported_name":"Brooks Vincent K","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2026-02-10T21:10:34.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":false,"shares":11564,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The restricted stock units awarded vested on February 6, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on February 6, 2026."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0001628280-26-006835","document":"wk-form4_1770757831.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006835/wk-form4_1770757831.xml","form_type":"4"}},{"id":912373,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":45266,"kind":"person","name":"Brooks Vincent K","position":1,"cik":"0001809046","reported_name":"Brooks Vincent K","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:10:34.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":27462,"source":{"system":"sec-edgar","filing":"0001628280-26-006835","document":"wk-form4_1770757831.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006835/wk-form4_1770757831.xml","form_type":"4"}},{"id":912372,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":45266,"kind":"person","name":"Brooks Vincent K","position":1,"cik":"0001809046","reported_name":"Brooks Vincent K","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:10:34.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":true,"shares":11564,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents distribution of AMTM common stock upon vesting of restricted stock units."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Reflects a non-reportable transaction for shares transferred from the pro-rata distribution in-kind by Jacobs Solutions Inc. to its shareholders for no consideration on May 30, 2025."}],"balance_after":22400,"source":{"system":"sec-edgar","filing":"0001628280-26-006835","document":"wk-form4_1770757831.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006835/wk-form4_1770757831.xml","form_type":"4"}},{"id":912371,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":37506,"kind":"person","name":"EBERHART RALPH E","position":1,"cik":"0001409312","reported_name":"EBERHART RALPH E","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2026-02-10T21:09:36.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":false,"shares":11564,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The restricted stock units awarded vested on February 6, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on February 6, 2026."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0001628280-26-006831","document":"wk-form4_1770757772.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006831/wk-form4_1770757772.xml","form_type":"4"}},{"id":912370,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":37506,"kind":"person","name":"EBERHART RALPH E","position":1,"cik":"0001409312","reported_name":"EBERHART RALPH E","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:09:36.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":48120,"source":{"system":"sec-edgar","filing":"0001628280-26-006831","document":"wk-form4_1770757772.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006831/wk-form4_1770757772.xml","form_type":"4"}},{"id":912369,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":37506,"kind":"person","name":"EBERHART RALPH E","position":1,"cik":"0001409312","reported_name":"EBERHART RALPH E","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:09:36.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":true,"shares":11564,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents distribution of AMTM common stock upon vesting of restricted stock units."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Reflects a non-reportable transaction for shares transferred from the pro-rata distribution in-kind by Jacobs Solutions Inc. to its shareholders for no consideration on May 30, 2025."}],"balance_after":43058,"source":{"system":"sec-edgar","filing":"0001628280-26-006831","document":"wk-form4_1770757772.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006831/wk-form4_1770757772.xml","form_type":"4"}},{"id":912367,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":38467,"kind":"person","name":"Loughran Barbara","position":1,"cik":"0001778333","reported_name":"Loughran Barbara","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:08:04.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":9662,"source":{"system":"sec-edgar","filing":"0001628280-26-006828","document":"wk-form4_1770757680.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006828/wk-form4_1770757680.xml","form_type":"4"}},{"id":912368,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":67069,"kind":"person","name":"Thompson Christopher M.T.","position":1,"cik":"0001483410","reported_name":"Thompson Christopher M.T.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:07:26.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":5062,"source":{"system":"sec-edgar","filing":"0001628280-26-006827","document":"wk-form4_1770757643.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006827/wk-form4_1770757643.xml","form_type":"4"}},{"id":912366,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":67068,"kind":"person","name":"Vollmer John C.","position":1,"cik":"0001723342","reported_name":"Vollmer John C.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2026-02-10T21:05:59.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":false,"shares":11564,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The restricted stock units awarded vested on February 6, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on February 6, 2026."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0001628280-26-006820","document":"wk-form4_1770757555.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006820/wk-form4_1770757555.xml","form_type":"4"}},{"id":912365,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":67068,"kind":"person","name":"Vollmer John C.","position":1,"cik":"0001723342","reported_name":"Vollmer John C.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:05:59.000Z","date":"2026-02-06","kind":"grant","planned":false,"acquired":true,"shares":5062,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":429842,"source":{"system":"sec-edgar","filing":"0001628280-26-006820","document":"wk-form4_1770757555.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006820/wk-form4_1770757555.xml","form_type":"4"}},{"id":912364,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":67068,"kind":"person","name":"Vollmer John C.","position":1,"cik":"0001723342","reported_name":"Vollmer John C.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-02-10T21:05:59.000Z","date":"2026-02-06","kind":"exercise","planned":false,"acquired":true,"shares":11564,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents distribution of AMTM common stock upon vesting of restricted stock units."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Reflects a non-reportable transaction for shares transferred from the pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration at the time of the transaction."}],"balance_after":424780,"source":{"system":"sec-edgar","filing":"0001628280-26-006820","document":"wk-form4_1770757555.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026006820/wk-form4_1770757555.xml","form_type":"4"}},{"id":928005,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Restricted Stock Units","published_at":"2026-01-29T21:21:01.000Z","date":"2026-01-28","kind":"exercise","planned":false,"acquired":false,"shares":51979,"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 January 28, 2026."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on January 28, 2026."}],"balance_after":103959,"derivative":{"underlying":"Common Stock","underlying_shares":51979},"source":{"system":"sec-edgar","filing":"0001628280-26-004144","document":"wk-form4_1769721657.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026004144/wk-form4_1769721657.xml","form_type":"4"}},{"id":928004,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2026-01-29T21:21:01.000Z","date":"2026-01-28","kind":"tax_withholding","planned":false,"acquired":false,"shares":19768,"price":35.71,"value":705915.28,"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":366058,"source":{"system":"sec-edgar","filing":"0001628280-26-004144","document":"wk-form4_1769721657.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026004144/wk-form4_1769721657.xml","form_type":"4"}},{"id":928003,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2026-01-29T21:21:01.000Z","date":"2026-01-28","kind":"exercise","planned":false,"acquired":true,"shares":51979,"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":385826,"source":{"system":"sec-edgar","filing":"0001628280-26-004144","document":"wk-form4_1769721657.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828026004144/wk-form4_1769721657.xml","form_type":"4"}},{"id":962228,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Restricted Stock Units","published_at":"2025-12-19T21:19:04.000Z","date":"2025-12-17","kind":"exercise","planned":false,"acquired":false,"shares":9298,"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 December 17, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on December 17, 2025."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":9298},"source":{"system":"sec-edgar","filing":"0001628280-25-058286","document":"wk-form4_1766179141.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025058286/wk-form4_1766179141.xml","form_type":"4"}},{"id":962227,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2025-12-19T21:19:04.000Z","date":"2025-12-17","kind":"tax_withholding","planned":false,"acquired":false,"shares":4194,"price":28.67,"value":120241.98,"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":26138,"source":{"system":"sec-edgar","filing":"0001628280-25-058286","document":"wk-form4_1766179141.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025058286/wk-form4_1766179141.xml","form_type":"4"}},{"id":962226,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2025-12-19T21:19:04.000Z","date":"2025-12-17","kind":"exercise","planned":false,"acquired":true,"shares":9298,"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":30332,"source":{"system":"sec-edgar","filing":"0001628280-25-058286","document":"wk-form4_1766179141.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025058286/wk-form4_1766179141.xml","form_type":"4"}},{"id":976409,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":72002,"kind":"person","name":"Burton Darren","position":1,"cik":"0002044904","reported_name":"Burton Darren","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief People Officer"}}],"security":"Restricted Stock Units","published_at":"2025-12-09T16:28:42.000Z","date":"2025-12-05","kind":"exercise","planned":false,"acquired":false,"shares":2721,"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 December 5, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on December 5, 2025."}],"balance_after":5444,"derivative":{"underlying":"Common Stock","underlying_shares":2721},"source":{"system":"sec-edgar","filing":"0001628280-25-056097","document":"wk-form4_1765315717.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2044904/000162828025056097/wk-form4_1765315717.xml","form_type":"4"}},{"id":976408,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":72002,"kind":"person","name":"Burton Darren","position":1,"cik":"0002044904","reported_name":"Burton Darren","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief People Officer"}}],"security":"Common Stock","published_at":"2025-12-09T16:28:42.000Z","date":"2025-12-05","kind":"tax_withholding","planned":false,"acquired":false,"shares":1392,"price":28.88,"value":40200.96,"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":23600,"source":{"system":"sec-edgar","filing":"0001628280-25-056097","document":"wk-form4_1765315717.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2044904/000162828025056097/wk-form4_1765315717.xml","form_type":"4"}},{"id":976407,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":72002,"kind":"person","name":"Burton Darren","position":1,"cik":"0002044904","reported_name":"Burton Darren","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief People Officer"}}],"security":"Common Stock","published_at":"2025-12-09T16:28:42.000Z","date":"2025-12-05","kind":"exercise","planned":false,"acquired":true,"shares":2721,"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":24992,"source":{"system":"sec-edgar","filing":"0001628280-25-056097","document":"wk-form4_1765315717.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2044904/000162828025056097/wk-form4_1765315717.xml","form_type":"4"}},{"id":994186,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:53:50.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":17817,"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":21034,"source":{"system":"sec-edgar","filing":"0001628280-25-053285","document":"wk-form4_1763592827.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025053285/wk-form4_1763592827.xml","form_type":"4"}},{"id":994144,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:52:13.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":155897,"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":269440,"source":{"system":"sec-edgar","filing":"0001628280-25-053283","document":"wk-form4_1763592731.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025053283/wk-form4_1763592731.xml","form_type":"4"}},{"id":994219,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:49:47.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":17817,"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":21198,"source":{"system":"sec-edgar","filing":"0001628280-25-053280","document":"wk-form4_1763592584.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000162828025053280/wk-form4_1763592584.xml","form_type":"4"}},{"id":994143,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:45:40.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":100220,"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":108675,"source":{"system":"sec-edgar","filing":"0001628280-25-053276","document":"wk-form4_1763592337.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025053276/wk-form4_1763592337.xml","form_type":"4"}},{"id":994142,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-19T22:36:38.000Z","date":"2025-11-17","kind":"exercise","planned":false,"acquired":false,"shares":1178,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","text":"Each restricted stock unit represents a contingent right to receive one share of AMTM common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The restricted stock units awarded vested on November 17, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on November 17, 2025."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":1178},"source":{"system":"sec-edgar","filing":"0001628280-25-053268","document":"wk-form4_1763591795.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025053268/wk-form4_1763591795.xml","form_type":"4"}},{"id":994141,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:36:38.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":46769,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","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":93725,"source":{"system":"sec-edgar","filing":"0001628280-25-053268","document":"wk-form4_1763591795.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025053268/wk-form4_1763591795.xml","form_type":"4"}},{"id":994140,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:36:38.000Z","date":"2025-11-17","kind":"tax_withholding","planned":false,"acquired":false,"shares":287,"price":21.49,"value":6167.63,"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":46956,"source":{"system":"sec-edgar","filing":"0001628280-25-053268","document":"wk-form4_1763591795.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025053268/wk-form4_1763591795.xml","form_type":"4"}},{"id":994139,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-19T22:36:38.000Z","date":"2025-11-17","kind":"exercise","planned":false,"acquired":true,"shares":1178,"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":47243,"source":{"system":"sec-edgar","filing":"0001628280-25-053268","document":"wk-form4_1763591795.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025053268/wk-form4_1763591795.xml","form_type":"4"}},{"id":994285,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Restricted Stock Units","published_at":"2025-11-19T22:25:09.000Z","date":"2025-11-17","kind":"exercise","planned":false,"acquired":false,"shares":43396,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","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":"F5","text":"The restricted stock units awarded vested on November 17, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on November 17, 2025."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":43396},"source":{"system":"sec-edgar","filing":"0001628280-25-053259","document":"wk-form4_1763591106.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025053259/wk-form4_1763591106.xml","form_type":"4"}},{"id":994284,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Common Stock","published_at":"2025-11-19T22:25:09.000Z","date":"2025-11-17","kind":"grant","planned":false,"acquired":true,"shares":111355,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"The restricted stock units shall vest and be delivered on the first anniversary of November 17, 2025."}],"balance_after":820476,"source":{"system":"sec-edgar","filing":"0001628280-25-053259","document":"wk-form4_1763591106.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025053259/wk-form4_1763591106.xml","form_type":"4"}},{"id":994283,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Common Stock","published_at":"2025-11-19T22:25:09.000Z","date":"2025-11-17","kind":"tax_withholding","planned":false,"acquired":false,"shares":17077,"price":21.49,"value":366984.73,"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":709121,"source":{"system":"sec-edgar","filing":"0001628280-25-053259","document":"wk-form4_1763591106.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025053259/wk-form4_1763591106.xml","form_type":"4"}},{"id":994282,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Common Stock","published_at":"2025-11-19T22:25:09.000Z","date":"2025-11-17","kind":"exercise","planned":false,"acquired":true,"shares":43396,"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":726198,"source":{"system":"sec-edgar","filing":"0001628280-25-053259","document":"wk-form4_1763591106.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025053259/wk-form4_1763591106.xml","form_type":"4"}},{"id":994232,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":72002,"kind":"person","name":"Burton Darren","position":1,"cik":"0002044904","reported_name":"Burton Darren","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief People Officer"}}],"security":"Common Stock","published_at":"2025-11-19T17:47:42.000Z","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":"0001628280-25-053278","document":"wk-form4_1763592459.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2044904/000162828025053278/wk-form4_1763592459.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":996100,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"exercise","planned":false,"acquired":false,"shares":4596,"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":"F5","text":"The restricted stock units awarded vested on November 16, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on November 16, 2025."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":4596},"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":12,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996099,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"exercise","planned":false,"acquired":false,"shares":3681,"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":"F5","text":"The restricted stock units awarded vested on November 16, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on November 16, 2025."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":3681},"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":11,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996098,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"exercise","planned":false,"acquired":false,"shares":5053,"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":"F5","text":"The restricted stock units awarded vested on November 16, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The restricted stock units awarded vested on November 16, 2025."}],"balance_after":5053,"derivative":{"underlying":"Common Stock","underlying_shares":5053},"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":10,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996097,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-15","kind":"exercise","planned":false,"acquired":false,"shares":5758,"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 November 15, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 15, 2025."}],"balance_after":11515,"derivative":{"underlying":"Common Stock","underlying_shares":5758},"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":9,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996096,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"tax_withholding","planned":false,"acquired":false,"shares":1120,"price":22.07,"value":24718.4,"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":46065,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996095,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"exercise","planned":false,"acquired":true,"shares":4596,"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":47185,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996094,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"tax_withholding","planned":false,"acquired":false,"shares":897,"price":22.07,"value":19796.79,"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":42589,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996093,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"exercise","planned":false,"acquired":true,"shares":3681,"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":43486,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996092,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"tax_withholding","planned":false,"acquired":false,"shares":1231,"price":22.07,"value":27168.17,"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":39805,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996091,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-16","kind":"exercise","planned":false,"acquired":true,"shares":5053,"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":41036,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996090,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-15","kind":"tax_withholding","planned":false,"acquired":false,"shares":1403,"price":22.07,"value":30964.21,"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":35983,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":996089,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-18T21:57:11.000Z","date":"2025-11-15","kind":"exercise","planned":false,"acquired":true,"shares":5758,"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":37386,"source":{"system":"sec-edgar","filing":"0001628280-25-052958","document":"wk-form4_1763503027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025052958/wk-form4_1763503027.xml","form_type":"4"}},{"id":1003901,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-10T21:46:46.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":false,"shares":12097,"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 November 6, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 6, 2025."}],"balance_after":24194,"derivative":{"underlying":"Common Stock","underlying_shares":12097},"source":{"system":"sec-edgar","filing":"0001628280-25-051118","document":"wk-form4_1762811204.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051118/wk-form4_1762811204.xml","form_type":"4"}},{"id":1003900,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:46:46.000Z","date":"2025-11-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":3642,"price":21.79,"value":79359.18,"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":8455,"source":{"system":"sec-edgar","filing":"0001628280-25-051118","document":"wk-form4_1762811204.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051118/wk-form4_1762811204.xml","form_type":"4"}},{"id":1003899,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49138,"kind":"person","name":"Johnson Travis Barton","position":1,"cik":"0001795038","reported_name":"Johnson Travis Barton","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:46:46.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":true,"shares":12097,"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":12097,"source":{"system":"sec-edgar","filing":"0001628280-25-051118","document":"wk-form4_1762811204.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051118/wk-form4_1762811204.xml","form_type":"4"}},{"id":1003929,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-10T21:46:15.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":false,"shares":4838,"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 November 6, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 6, 2025."}],"balance_after":9678,"derivative":{"underlying":"Common Stock","underlying_shares":4838},"source":{"system":"sec-edgar","filing":"0001628280-25-051117","document":"wk-form4_1762811169.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000162828025051117/wk-form4_1762811169.xml","form_type":"4"}},{"id":1003928,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:46:15.000Z","date":"2025-11-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":1457,"price":21.79,"value":31748.03,"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":3381,"source":{"system":"sec-edgar","filing":"0001628280-25-051117","document":"wk-form4_1762811169.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000162828025051117/wk-form4_1762811169.xml","form_type":"4"}},{"id":1003927,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49147,"kind":"person","name":"Bruning Jill L","position":1,"cik":"0002037037","reported_name":"Bruning Jill L","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:46:15.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":true,"shares":4838,"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":4838,"source":{"system":"sec-edgar","filing":"0001628280-25-051117","document":"wk-form4_1762811169.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037037/000162828025051117/wk-form4_1762811169.xml","form_type":"4"}},{"id":1003893,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-10T21:45:22.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":false,"shares":39617,"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 November 6, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 6, 2025."}],"balance_after":79236,"derivative":{"underlying":"Common Stock","underlying_shares":39617},"source":{"system":"sec-edgar","filing":"0001628280-25-051115","document":"wk-form4_1762811119.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051115/wk-form4_1762811119.xml","form_type":"4"}},{"id":1003892,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:45:22.000Z","date":"2025-11-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":17868,"price":21.79,"value":389343.72,"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":113543,"source":{"system":"sec-edgar","filing":"0001628280-25-051115","document":"wk-form4_1762811119.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051115/wk-form4_1762811119.xml","form_type":"4"}},{"id":1003891,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49139,"kind":"person","name":"Heller John E.","position":1,"cik":"0001552715","reported_name":"Heller John E.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Executive Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:45:22.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":true,"shares":39617,"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":131411,"source":{"system":"sec-edgar","filing":"0001628280-25-051115","document":"wk-form4_1762811119.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051115/wk-form4_1762811119.xml","form_type":"4"}},{"id":1003925,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-10T21:44:44.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":false,"shares":4838,"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 November 6, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 6, 2025."}],"balance_after":9678,"derivative":{"underlying":"Common Stock","underlying_shares":4838},"source":{"system":"sec-edgar","filing":"0001628280-25-051113","document":"wk-form4_1762811081.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025051113/wk-form4_1762811081.xml","form_type":"4"}},{"id":1003924,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:44:44.000Z","date":"2025-11-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":1621,"price":21.79,"value":35321.59,"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":3217,"source":{"system":"sec-edgar","filing":"0001628280-25-051113","document":"wk-form4_1762811081.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025051113/wk-form4_1762811081.xml","form_type":"4"}},{"id":1003923,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49146,"kind":"person","name":"Mullen Sean Thomas","position":1,"cik":"0002034388","reported_name":"Mullen Sean Thomas","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Growth Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:44:44.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":true,"shares":4838,"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":4838,"source":{"system":"sec-edgar","filing":"0001628280-25-051113","document":"wk-form4_1762811081.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2034388/000162828025051113/wk-form4_1762811081.xml","form_type":"4"}},{"id":1004090,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Restricted Stock Units","published_at":"2025-11-10T21:44:01.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":false,"shares":90727,"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 November 6, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 6, 2025."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":90727},"source":{"system":"sec-edgar","filing":"0001628280-25-051110","document":"wk-form4_1762811038.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025051110/wk-form4_1762811038.xml","form_type":"4"}},{"id":1004089,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Common Stock","published_at":"2025-11-10T21:44:01.000Z","date":"2025-11-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":28818,"price":21.79,"value":627944.22,"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":682802,"source":{"system":"sec-edgar","filing":"0001628280-25-051110","document":"wk-form4_1762811038.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025051110/wk-form4_1762811038.xml","form_type":"4"}},{"id":1004088,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":32300,"kind":"person","name":"DEMETRIOU STEVEN J.","position":1,"cik":"0001173003","reported_name":"DEMETRIOU STEVEN J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Executive Chair"}}],"security":"Common Stock","published_at":"2025-11-10T21:44:01.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":true,"shares":90727,"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":711620,"source":{"system":"sec-edgar","filing":"0001628280-25-051110","document":"wk-form4_1762811038.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1173003/000162828025051110/wk-form4_1762811038.xml","form_type":"4"}},{"id":1003896,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Restricted Stock Units","published_at":"2025-11-10T21:42:15.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":false,"shares":12701,"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 November 6, 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The restricted stock units awarded vested on November 6, 2025."}],"balance_after":25404,"derivative":{"underlying":"Common Stock","underlying_shares":12701},"source":{"system":"sec-edgar","filing":"0001628280-25-051106","document":"wk-form4_1762810932.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051106/wk-form4_1762810932.xml","form_type":"4"}},{"id":1003895,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:42:15.000Z","date":"2025-11-06","kind":"tax_withholding","planned":false,"acquired":false,"shares":3093,"price":21.79,"value":67396.47,"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":31628,"source":{"system":"sec-edgar","filing":"0001628280-25-051106","document":"wk-form4_1762810932.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051106/wk-form4_1762810932.xml","form_type":"4"}},{"id":1003894,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":49136,"kind":"person","name":"Arnette Stephen A","position":1,"cik":"0001919492","reported_name":"Arnette Stephen A","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Operating Officer"}}],"security":"Common Stock","published_at":"2025-11-10T21:42:15.000Z","date":"2025-11-06","kind":"exercise","planned":false,"acquired":true,"shares":12701,"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":34721,"source":{"system":"sec-edgar","filing":"0001628280-25-051106","document":"wk-form4_1762810932.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000162828025051106/wk-form4_1762810932.xml","form_type":"4"}},{"id":1152462,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":79920,"kind":"organization","name":"Lindsay Goldberg Employee Co-Inv. IV L.P.","position":1,"cik":"0002037350","reported_name":"Lindsay Goldberg Employee Co-Inv. IV L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79921,"kind":"organization","name":"LG Co-Inv. A L.P.","position":2,"cik":"0002037394","reported_name":"LG Co-Inv. A L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79922,"kind":"organization","name":"Lindsay Goldberg V L.P.","position":3,"cik":"0001743020","reported_name":"Lindsay Goldberg V L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79923,"kind":"organization","name":"Lindsay Goldberg Maverick Co-Inv. L.P.","position":4,"cik":"0002037408","reported_name":"Lindsay Goldberg Maverick Co-Inv. L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79924,"kind":"organization","name":"LG Amentum Holdings GP LLC","position":5,"cik":"0002037417","reported_name":"LG Amentum Holdings GP LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79925,"kind":"organization","name":"LG Amentum Holdings LP","position":6,"cik":"0002037445","reported_name":"LG Amentum Holdings LP","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2025-05-12T16:30:19.000Z","date":"2025-05-08","kind":"other","planned":false,"acquired":true,"shares":1132839,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents securities received in a pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents securities received in a pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Goldberg is the Managing Member of Goldberg 2014 LLC and the Manager of Goldberg 2020 LLC. Goldberg 2014 LLC is the Active Member (and thereby, the manager) of LG GP Holding IV LLC, which is the managing member of Lindsay Goldberg GP IV LLC, which is the general partner of each of Lindsay Goldberg IV L.P., Lindsay Goldberg IV - A L.P., Lindsay Goldberg IV - PCF L.P., Lindsay Goldberg Co-Inv. IV L.P. and Lindsay Goldberg Employee Co-Inv. IV L.P (together, the \"LG Fund IV Partnerships\"). Goldberg 2020 LLC is the Manager of LG GP Holding V LLC, which is the managing member of Lindsay Goldberg GP V LLC, which is the general partner of each of Lindsay Goldberg V L.P. and Lindsay Goldberg Maverick Co-Inv. L.P. (together, the \"LG Fund V Partnerships\")."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Each of Lindsay Goldberg GP IV LLC and Lindsay Goldberg GP V LLC are the general partners of LG Co-Inv. A LP. Each of the LG Fund IV Partnerships, the LG Fund V Partnerships and LG Co-Inv. A LP are members of LG Amentum Holdings GP LLC, which is the general partner of LG Amentum Holdings LP. Each of the Reporting Persons other than LG Amentum Holdings LP may be deemed to share beneficial ownership of the Common Shares directly held by LG Amentum Holdings LP."}],"balance_after":45026743,"source":{"system":"sec-edgar","filing":"0001641172-25-009710","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037394/000164117225009710/ownership.xml","form_type":"4"}},{"id":1152702,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":79952,"kind":"person","name":"GOLDBERG ALAN E","position":1,"cik":"0001077430","reported_name":"GOLDBERG ALAN E","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2025-05-12T16:30:16.000Z","date":"2025-05-08","kind":"other","planned":false,"acquired":true,"shares":1132839,"ownership":{"direct":false,"nature":"By LG Amentum Holdings LP"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents securities received in a pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents securities received in a pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration."}],"balance_after":45026743,"source":{"system":"sec-edgar","filing":"0001641172-25-009708","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1077430/000164117225009708/ownership.xml","form_type":"4"}},{"id":1152463,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":79926,"kind":"organization","name":"Goldberg 2014 LLC","position":1,"cik":"0002037981","reported_name":"Goldberg 2014 LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79927,"kind":"organization","name":"Goldberg 2020 LLC","position":2,"cik":"0002037424","reported_name":"Goldberg 2020 LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79928,"kind":"organization","name":"LG GP Holding IV LLC","position":3,"cik":"0002038310","reported_name":"LG GP Holding IV LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79929,"kind":"organization","name":"LG GP Holding V LLC","position":4,"cik":"0002037432","reported_name":"LG GP Holding V LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79930,"kind":"organization","name":"Lindsay Goldberg GP IV LLC","position":5,"cik":"0002037399","reported_name":"Lindsay Goldberg GP IV LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79931,"kind":"organization","name":"Lindsay Goldberg GP V LLC","position":6,"cik":"0002037542","reported_name":"Lindsay Goldberg GP V LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79932,"kind":"organization","name":"Lindsay Goldberg IV L.P.","position":7,"cik":"0001605108","reported_name":"Lindsay Goldberg IV L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79933,"kind":"organization","name":"Lindsay Goldberg IV - A L.P.","position":8,"cik":"0001605152","reported_name":"Lindsay Goldberg IV - A L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79934,"kind":"organization","name":"Lindsay Goldberg IV - PCF L.P.","position":9,"cik":"0001605154","reported_name":"Lindsay Goldberg IV - PCF L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":79935,"kind":"organization","name":"Lindsay Goldberg Co-Inv. IV L.P.","position":10,"cik":"0002037459","reported_name":"Lindsay Goldberg Co-Inv. IV L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2025-05-12T16:30:14.000Z","date":"2025-05-08","kind":"other","planned":false,"acquired":true,"shares":1132839,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents securities received in a pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Represents securities received in a pro-rata distribution in-kind by Amentum Joint Venture LP to its partners for no consideration."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Goldberg is the Managing Member of Goldberg 2014 LLC and the Manager of Goldberg 2020 LLC. Goldberg 2014 LLC is the Active Member (and thereby, the manager) of LG GP Holding IV LLC, which is the managing member of Lindsay Goldberg GP IV LLC, which is the general partner of each of Lindsay Goldberg IV L.P., Lindsay Goldberg IV - A L.P., Lindsay Goldberg IV - PCF L.P., Lindsay Goldberg Co-Inv. IV L.P. and Lindsay Goldberg Employee Co-Inv. IV L.P (together, the \"LG Fund IV Partnerships\"). Goldberg 2020 LLC is the Manager of LG GP Holding V LLC, which is the managing member of Lindsay Goldberg GP V LLC, which is the general partner of each of Lindsay Goldberg V L.P. and Lindsay Goldberg Maverick Co-Inv. L.P. (together, the \"LG Fund V Partnerships\")."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Each of Lindsay Goldberg GP IV LLC and Lindsay Goldberg GP V LLC are the general partners of LG Co-Inv. A LP. Each of the LG Fund IV Partnerships, the LG Fund V Partnerships and LG Co-Inv. A LP are members of LG Amentum Holdings GP LLC, which is the general partner of LG Amentum Holdings LP. Each of the Reporting Persons other than LG Amentum Holdings LP may be deemed to share beneficial ownership of the Common Shares directly held by LG Amentum Holdings LP."}],"balance_after":45026743,"source":{"system":"sec-edgar","filing":"0001641172-25-009707","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037981/000164117225009707/ownership.xml","form_type":"4"}},{"id":1152464,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":79936,"kind":"person","name":"Amentum Joint Venture GP LLC","position":1,"cik":"0002037401","reported_name":"Amentum Joint Venture GP LLC","relationship":{"director":true}},{"id":79937,"kind":"person","name":"Amentum Joint Venture LP","position":2,"cik":"0002037182","reported_name":"Amentum Joint Venture LP","relationship":{"director":true}}],"security":"Common Stock","published_at":"2025-05-12T09:07:42.000Z","date":"2025-05-08","kind":"other","planned":false,"acquired":false,"shares":2433022,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Amentum Joint Venture LP"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This Form 4 is filed jointly by (i) Amentum Joint Venture GP LLC and (ii) Amentum Joint Venture LP (\"Amentum JV\"). Amentum Joint Venture GP LLC is the general partner of Amentum JV and may be deemed to have indirect voting and investment control over the shares held by Amentum JV.  The shares of the Issuer reported as disposed in this Form 4 were owned directly by Amentum JV as a result of a Reverse Morris Trust transaction, with the Issuer surviving and being renamed Amentum Holdings, Inc., pursuant to the merger agreement and separation and distribution agreement, each dated as of November 20, 2023, among, in each case, Jacobs Solutions, Inc., the Issuer, Amentum Parent Holdings LLC and Amentum JV (as amended). The purpose of this Form 4 is to report that the Reporting Persons no longer beneficially own any shares of the Issuer."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"On May 8, 2025, Amentum JV made pro rata distributions-in-kind of all of the shares of the Issuer held by Amentum JV to each of its limited partners in accordance with the limited partnership agreement of Amentum JV.  As a result, Amentum JV no longer holds, and each of the Reporting Persons no longer beneficially owns, any shares of the Issuer."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"This Form 4 is filed jointly by (i) Amentum Joint Venture GP LLC and (ii) Amentum Joint Venture LP (\"Amentum JV\"). Amentum Joint Venture GP LLC is the general partner of Amentum JV and may be deemed to have indirect voting and investment control over the shares held by Amentum JV.  The shares of the Issuer reported as disposed in this Form 4 were owned directly by Amentum JV as a result of a Reverse Morris Trust transaction, with the Issuer surviving and being renamed Amentum Holdings, Inc., pursuant to the merger agreement and separation and distribution agreement, each dated as of November 20, 2023, among, in each case, Jacobs Solutions, Inc., the Issuer, Amentum Parent Holdings LLC and Amentum JV (as amended). The purpose of this Form 4 is to report that the Reporting Persons no longer beneficially own any shares of the Issuer."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"This Form 4 is filed jointly by (i) Amentum Joint Venture GP LLC and (ii) Amentum Joint Venture LP (\"Amentum JV\"). Amentum Joint Venture GP LLC is the general partner of Amentum JV and may be deemed to have indirect voting and investment control over the shares held by Amentum JV.  The shares of the Issuer reported as disposed in this Form 4 were owned directly by Amentum JV as a result of a Reverse Morris Trust transaction, with the Issuer surviving and being renamed Amentum Holdings, Inc., pursuant to the merger agreement and separation and distribution agreement, each dated as of November 20, 2023, among, in each case, Jacobs Solutions, Inc., the Issuer, Amentum Parent Holdings LLC and Amentum JV (as amended). The purpose of this Form 4 is to report that the Reporting Persons no longer beneficially own any shares of the Issuer."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"On May 8, 2025, Amentum JV made pro rata distributions-in-kind of all of the shares of the Issuer held by Amentum JV to each of its limited partners in accordance with the limited partnership agreement of Amentum JV.  As a result, Amentum JV no longer holds, and each of the Reporting Persons no longer beneficially owns, any shares of the Issuer."}],"balance_after":0,"source":{"system":"sec-edgar","filing":"0000950157-25-000397","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2037401/000095015725000397/form4.xml","form_type":"4"}},{"id":1174215,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":67068,"kind":"person","name":"Vollmer John C.","position":1,"cik":"0001723342","reported_name":"Vollmer John C.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2025-04-10T20:41:09.000Z","date":"2025-04-08","kind":"grant","planned":false,"acquired":true,"shares":11564,"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":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":11564,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0002011286-25-000117","document":"wk-form4_1744317662.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128625000117/wk-form4_1744317662.xml","form_type":"4"}},{"id":1174214,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":45266,"kind":"person","name":"Brooks Vincent K","position":1,"cik":"0001809046","reported_name":"Brooks Vincent K","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2025-04-10T20:40:58.000Z","date":"2025-04-08","kind":"grant","planned":false,"acquired":true,"shares":11564,"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":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":11564,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0002011286-25-000116","document":"wk-form4_1744317652.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128625000116/wk-form4_1744317652.xml","form_type":"4"}},{"id":1174213,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":37506,"kind":"person","name":"EBERHART RALPH E","position":1,"cik":"0001409312","reported_name":"EBERHART RALPH E","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2025-04-10T20:40:49.000Z","date":"2025-04-08","kind":"grant","planned":false,"acquired":true,"shares":11564,"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":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":11564,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0002011286-25-000115","document":"wk-form4_1744317641.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128625000115/wk-form4_1744317641.xml","form_type":"4"}},{"id":1174212,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":38467,"kind":"person","name":"Loughran Barbara","position":1,"cik":"0001778333","reported_name":"Loughran Barbara","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2025-04-10T20:40:38.000Z","date":"2025-04-08","kind":"grant","planned":false,"acquired":true,"shares":11564,"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":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":11564,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0002011286-25-000114","document":"wk-form4_1744317632.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128625000114/wk-form4_1744317632.xml","form_type":"4"}},{"id":1174211,"issuer":{"id":3920,"kind":"organization","name":"Amentum Holdings, Inc.","symbol":"AMTM"},"owners":[{"id":15111,"kind":"person","name":"IRELAND SUSAN LESLIE","position":1,"cik":"0001718953","reported_name":"IRELAND SUSAN LESLIE","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2025-04-10T20:40:28.000Z","date":"2025-04-08","kind":"grant","planned":false,"acquired":true,"shares":11564,"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":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The restricted stock units shall vest on the date of the next annual meeting of stockholders of the Issuer."}],"balance_after":11564,"derivative":{"underlying":"Common Stock","underlying_shares":11564},"source":{"system":"sec-edgar","filing":"0002011286-25-000113","document":"wk-form4_1744317621.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2011286/000201128625000113/wk-form4_1744317621.xml","form_type":"4"}}],"next_cursor":"2025-04-10T20:40:28.000000Z,1174211"}