Segment Information

12 Months Ended

Oct. 03, 2025

Segment Reporting [Abstract]

Segment Information

Segment Information

We operate our business activities and report financial results as two reportable segments: Digital Solutions (“DS”) and Global Engineering Solutions (“GES”).

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.

The presentation of financial results as two reportable segments is consistent with the way the Company operates its business and the manner in which our chief operating decision maker (“CODM”), currently our Chief Executive Officer, manages the operations of the Company for purposes of allocating resources and assessing performance. The CODM evaluates the performance of our segments based on revenues and Adjusted EBITDA. Adjusted EBITDA is most comparable to net income (loss) attributable to common shareholders prepared based on GAAP. The Company defines Adjusted EBITDA as net income (loss) attributable to common shareholders adjusted for interest expense and other, net, provision for income taxes, depreciation and amortization, and certain discrete items that are not considered in the evaluation of ongoing operating performance. These discrete items include acquisition, transaction, and integration costs, non-cash gains and losses, loss on extinguishment of debt, utilization of certain fair market value adjustments assigned in purchase accounting, and stock-based compensation. While we believe Adjusted EBITDA is a useful metric in evaluating operating performance by allowing better evaluation of underlying segment performance and better period-to-period comparability, it is not a metric defined by GAAP and may not be comparable to non-GAAP metrics presented by other companies.

In fiscal year 2025, the Company adopted ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. Amongst other amendments, the standard requires disclosure of significant segment expenses that are

regularly provided to the CODM. Cost of revenues is the significant expense that is regularly provided to the Company's CODM, and includes direct contract costs such as labor, materials, and subcontractor costs, allocations of indirect costs, and depreciation expense related to property and equipment directly attributable to contracts.

The following table presents segment information provided to the CODM and reconciles segment Adjusted EBITDA to net income (loss) attributable to common shareholders, with prior year performance measures recast to reflect the current reportable segment structure:

	For the years ended
	October 3, 2025						September 27, 2024						September 29, 2023
(Amounts in millions)	DS		GES		Total		DS		GES		Total		DS		GES		Total
Revenues	$	5,543	$	8,850	$	14,393	$	1,981	$	6,407	$	8,388	$	1,899	$	5,966	$	7,865
Cost of revenues	(4,924)		(7,956)		(12,880)		(1,761)		(5,829)		(7,590)		(1,659)		(5,424)		(7,083)
Other segment expenses (1)	(182)		(227)		(409)		(61)		(119)		(180)		(81)		(105)		(186)
Adjusted EBITDA attributable to Amentum Holdings, Inc.	$	437	$	667	$	1,104	$	159	$	459	$	618	$	159	$	437	$	596
Depreciation expense					(40)						(23)						(27)
Amortization of intangibles					(479)						(228)						(298)
Interest expense and other, net					(353)						(438)						(397)
Non-controlling interests					(7)						(1)						(7)
Acquisition, transaction and integration costs (2)					(85)						(62)						(39)
Non-cash GAAP expense (gain) (3)					—						69						(186)
Loss on extinguishment of debt (4)					(12)						(45)						—
Utilization of fair market value adjustments (5)					8						5						21
Stock-based compensation (6)					(21)						(18)						(3)
Income (loss) before income taxes					115						(123)						(340)
Provision for income taxes					(56)						40						19
Net income (loss) including non-controlling interests					59						(83)						(321)
Net income (loss) attributable to non-controlling interests					7						1						7
Net income (loss) attributable to common shareholders					$	66					$	(82)					$	(314)

(1)    Represents the difference between segment revenues, costs of revenues, and Adjusted EBITDA attributable to Amentum Holdings, Inc. Other segment expenses primarily includes selling, general, and administrative expenses, and equity earnings of non-consolidated subsidiaries and excludes certain discrete items that are not considered in the evaluation of ongoing performance.

(2)    Represents acquisition, transaction and integration costs, including severance, retention, and other adjustments related to acquisition and integration activities.

(3)    Represents a non-cash goodwill impairment charge and a non-cash gain on acquisition of controlling interest.

(4)    Represents the write-off of debt discount and debt issuance costs as a result of debt modifications.

(5)    Represents the periodic utilization of the fair market value adjustments assigned to certain equity method investments and non-controlling interests based on the remaining period of performance for the related contract.

(6)    Represents non-cash compensation expenses recognized for stock-based arrangements.

Asset information by segment is not a key measure of performance used by the CODM.