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Organization and Description of Business | 12 Months Ended
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Oct. 03, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract] |
Organization and Description of Business | Organization and Description of Business Amentum Holdings, Inc. (collectively with its subsidiaries, “we,” “us,” “our,” “Amentum,” or the “Company”) is a global advanced engineering and technology solutions provider to a broad base of U.S. and allied government agencies, and customers in international and commercial markets, supporting programs of critical national importance across energy and environmental, intelligence, space, defense, civilian and commercial end-markets. We offer a broad reach of capabilities including energy, environmental remediation, intelligence and counter threat solutions, data fusion and analytics, engineering and integration, advanced test, training and readiness, and citizen solutions. As a leading provider of differentiated technology solutions, we have built a repertoire of deep customer knowledge, enabling us to engage our customers across multiple capabilities and markets. On September 27, 2024, the spin-off of the Jacobs Solutions Inc. (“Jacobs”) Critical Mission Solutions business and portions of the Jacobs Divergent Solutions business (and, together with the Critical Mission Solutions business, referred to as “CMS”) merged with Amentum Parent Holdings LLC (collectively, the “Transaction”) with the surviving entity renamed Amentum Holdings, Inc. We conduct our business activities and report financial results as two reportable segments: Digital Solutions and Global Engineering Solutions. The Digital Solutions segment provides advanced digital and data-driven solutions including intelligence analytics, space system development, cybersecurity, and next generation IT across the federal government and commercial clients. The Global Engineering Solutions segment provides large-scale environmental remediation, nuclear power solutions, platform engineering, sustainment and supply chain management across all seven continents for the U.S. government and allied nations. Amentum's Registration Statement on Form 10 (the “Registration Statement”), filed with the Securities and Exchange Commission (“SEC”) on July 15, 2024, was declared effective on September 18, 2024. Amentum Parent Holdings LLC is the accounting acquirer of CMS for accounting purposes in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Amentum Parent Holdings LLC is considered the Company’s predecessor and the historical financial statements of Amentum Parent Holdings LLC prior to September 27, 2024, are reflected in this Annual Report on Form 10-K as the Company’s historical financial statements. Accordingly, the financial results of the Company prior to September 27, 2024 do not include the financial results of CMS and current and future results will not be comparable to historical results.

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