Amentum Holdings, Inc. (AMTM) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

244,444,444Shares Outstanding

45,754,189Shares held by institutions

$1,374,913,379Value of institutional holdings

74.44%Institutional ownership %

12.83%Shares Changed QoQ

450No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

The institutional landscape for Amentum Holdings, Inc. (NYSE:AMTM) includes 450 filers as of the latest reporting cycle ending December 2025.

These investors collectively held 74.4% of the company's total shares outstanding in December 2025, down from 77.5% in September 2025.
On a quarter-over-quarter basis, institutional holdings shifted by 12.83%, with a year-over-year an increase of 1.35% in the count of filers.
The latest 13F cycle for Amentum Holdings reveals that of 450 total investors, 209 funds grew their exposure, whereas 146 reduced theirs and 95 made no changes.
This class of investors increased its holdings in Amentum Holdings to 181.95Mn shares for the 13F-cycle ending December 2025, up by 20.69Mn shares quarter on quarter, and up 12.52Mn shares year over year.
The top institutional stake in Amentum Holdings as of December 31, 2025 belongs to AMERICAN SECURITIES LLC, which owns 45.03Mn shares, or 18.42% of the company.
Among the most significant buyers of Amentum Holdings during December 2025 were Legacy Advisors, LLC (9.81Mn), Focus Partners Wealth (2.76Mn), NORGES BANK (2.29Mn), COOPER CREEK PARTNERS MANAGEMENT LLC (1.55Mn), AQR CAPITAL MANAGEMENT LLC (1.29Mn).
Leading sellers of Amentum Holdings stock in December 2025 included STATE STREET CORP (1.77Mn), THOMPSON SIEGEL & WALMSLEY LLC (808.49K), Point72 Asset Management, L.P. (685.71K), MILLENNIUM MANAGEMENT LLC (579.61K), BlackRock, Inc. (531.35K).
The top 10 institutional holders of Amentum Holdings for the quarter ending December 2025 included AMERICAN SECURITIES LLC (45.03Mn), BlackRock, Inc. (17.46Mn), VANGUARD GROUP INC (15.41Mn), PRIMECAP MANAGEMENT CO/CA/ (12.13Mn), Legacy Advisors, LLC (9.81Mn), FMR LLC (6.71Mn), FRONTIER CAPITAL MANAGEMENT CO LLC (5.77Mn), STATE STREET CORP (5.06Mn), Focus Partners Wealth (2.79Mn), GEODE CAPITAL MANAGEMENT, LLC (2.66Mn).

450 Institutional Holders

45,754,189 Total Shares Held

Rows:

Download Data

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
AMERICAN SECURITIES LLC	31 Dec, 2025	45,026,743	0	0.00%	$1,305,775,547.00
BlackRock, Inc.	31 Dec, 2025	17,459,099	-531,350	-2.95%	$506,313,859.00
VANGUARD GROUP INC	31 Dec, 2025	15,411,745	-142,946	-0.92%	$446,940,605.00
PRIMECAP MANAGEMENT CO/CA/	31 Dec, 2025	12,126,927	208,341	1.75%	$351,680,883.00
Legacy Advisors, LLC	31 Dec, 2025	9,814,289	9,814,289	0.00%	$9,814,597.00
FMR LLC	31 Dec, 2025	6,707,304	472,055	7.57%	$194,511,815.00
FRONTIER CAPITAL MANAGEMENT CO LLC	31 Dec, 2025	5,772,976	570,296	10.96%	$167,416,293.00
STATE STREET CORP	31 Dec, 2025	5,061,620	-1,771,756	-25.93%	$146,786,980.00
Focus Partners Wealth	31 Dec, 2025	2,794,417	2,761,801	8,467.63%	$81,038,102.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	2,659,364	5,180	0.20%	$77,145,389.00
Ruane, Cunniff & Goldfarb L.P.	31 Dec, 2025	2,394,129	-29,619	-1.22%	$69,429,741.00
NORGES BANK	31 Dec, 2025	2,294,097	2,294,097	0.00%	$66,528,813.00
MORGAN STANLEY	31 Dec, 2025	2,075,352	268,935	14.89%	$60,185,252.00
THRIVENT FINANCIAL FOR LUTHERANS	31 Dec, 2025	2,069,104	263,693	14.61%	$60,004.00
MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.	31 Dec, 2025	1,961,927	-119,684	-5.75%	$56,895,904.00
CHARLES SCHWAB INVESTMENT MANAGEMENT INC	31 Dec, 2025	1,952,002	109,831	5.96%	$56,608,065.00
THOMPSON SIEGEL & WALMSLEY LLC	31 Dec, 2025	1,921,809	-808,489	-29.61%	$55,732.00
DIMENSIONAL FUND ADVISORS LP	31 Dec, 2025	1,832,926	526,875	40.34%	$53,156,787.00
Arvin Capital Management LP	31 Dec, 2025	1,800,992	164,500	10.05%	$52,228,768.00
COOPER CREEK PARTNERS MANAGEMENT LLC	31 Dec, 2025	1,553,074	1,553,074	0.00%	$45,039.00

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