Amentum Holdings AMTM Institutional Ownership

NYSE AMTM

$18.43 +0.31 (+1.71%)

As of: Oct 1, 2026 · 9:44 AM EDT

Institutions by Trading Activity

466 Institutions

Increased 212 45.5%

Unchanged 100 21.5%

Reduced 154 33.0%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

90.64%

▲+4.15 pp QoQ

Shares Held by Institutions

221.17Mn

of 244.00Mn outstanding

▲+7.94% QoQ

Shares Outstanding

244.00Mn

22.83Mn held outside 13F filers

Institutional Investors

466

filed 13F for Jun 2026

▼-19 vs prior quarter

Net Shares Added (QoQ)

+16.26Mn

accumulated since last quarter

Value of Holdings

$4.01Bn

reported market value

Shares Owned by Institutions

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Institutions

Accumulated Distributed

Latest quarter —

Net over range —

Accumulating quarters —

Ownership Summary

Quarter ending 30 Jun, 2026

Amentum Holdings, Inc. (NYSE:AMTM) appears in 466 institutional 13F filings for the quarter ending June 2026.

These investors held 90.6% of outstanding shares in June 2026, up from 86.5% in March 2026.
They increased total shares held in Amentum Holdings by 7.94% from last quarter, and the number of investors in AMTM increased 1.08% annually.
During the quarter, 212 of these 466 funds increased positions in AMTM, 154 reduced exposure, and 100 held steady.
Altogether, these fund groups held 221.17Mn shares in AMTM by June 2026, up by 16.26Mn shares quarter on quarter, and up 23.34Mn shares year over year.
AMERICAN SECURITIES LLC is the top holder of Amentum Holdings as of June 30, 2026, with 45.03Mn shares representing 18.45% of outstanding stock.
The most significant purchases of AMTM for the quarter ending June 2026 came from Invesco Ltd. (3.48Mn), Troluce Capital Advisors LLC (2.57Mn), Sixth Street Partners Management Company, L.P. (2.12Mn), DIMENSIONAL FUND ADVISORS LP (1.75Mn), Goldman Sachs Group Inc (1.58Mn).
The largest sellers of Amentum Holdings for the quarter ending June 2026 were Focus Partners Wealth (2.47Mn), Arvin Capital Management LP (1.65Mn), Ruane, Cunniff & Goldfarb L.P. (1.09Mn), Point72 Asset Management, L.P. (980.58K), FRONTIER CAPITAL MANAGEMENT CO LLC (786.24K).
Business Quant data shows the 10 biggest positions in Amentum Holdings as of June 2026 are held by AMERICAN SECURITIES LLC (45.03Mn), Invesco Ltd. (24.95Mn), BlackRock, Inc. (17.91Mn), PRIMECAP MANAGEMENT CO/CA/ (12.29Mn), Legacy Advisors, LLC (9.07Mn), VANGUARD PORTFOLIO MANAGEMENT LLC (7.95Mn), VANGUARD CAPITAL MANAGEMENT LLC (6.71Mn), FMR LLC (5.68Mn), DIMENSIONAL FUND ADVISORS LP (5.54Mn), State Street Corp (5.15Mn).

Form 13F Holdings

465 Institutional Holders

Report period 30 Jun, 2026

Total shares held 221.17Mn

Of outstanding 90.64%

#	Institution	CIK	Shares Held	% of Outstanding	Change (QoQ)	Change (%)	Value (USD)
1	AMERICAN SECURITIES LLC	0001475483	45,026,743	18.45%	0	0.00%	$930.70Mn
2	Invesco Ltd.	0000914208	24,954,251	10.23%	▲3,480,473	+16.21%	$515.80Mn
3	BlackRock, Inc.	0002012383	17,906,984	7.34%	▲65,701	+0.37%	$370.14Mn
4	PRIMECAP MANAGEMENT CO/CA/	0000763212	12,285,504	5.04%	▲200,210	+1.66%	$253.94Mn
5	Legacy Advisors, LLC	0001720969	9,065,677	3.72%	▲1,399	+0.02%	$9.07Mn
6	VANGUARD PORTFOLIO MANAGEMENT LLC	0002100121	7,948,385	3.26%	▲95,434	+1.22%	$164.29Mn
7	VANGUARD CAPITAL MANAGEMENT LLC	0002100119	6,711,987	2.75%	▲61,108	+0.92%	$138.74Mn
8	FMR LLC	0000315066	5,679,175	2.33%	▲100,789	+1.81%	$117.39Mn
9	DIMENSIONAL FUND ADVISORS LP	0000354204	5,537,696	2.27%	▲1,750,276	+46.21%	$114.46Mn
10	State Street Corp	0000093751	5,151,772	2.11%	▲72,731	+1.43%	$106.49Mn
11	FRONTIER CAPITAL MANAGEMENT CO LLC	0000351173	4,143,971	1.70%	▼786,239	-15.95%	$85.66Mn
12	Troluce Capital Advisors LLC	0001910321	3,565,399	1.46%	▲2,565,399	+256.54%	$73.70Mn
13	GEODE CAPITAL MANAGEMENT, LLC	0001214717	2,716,560	1.11%	▼97,855	-3.48%	$56.17Mn
14	Goldman Sachs Group Inc	0000886982	2,711,866	1.11%	▲1,580,428	+139.68%	$56.05Mn
15	Morgan Stanley	0000895421	2,662,329	1.09%	▲427,416	+19.12%	$55.03Mn
16	MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.	0001705339	2,318,581	0.95%	▼466,553	-16.75%	$47.93Mn
17	THOMPSON SIEGEL & WALMSLEY LLC	0001008322	2,281,945	0.94%	▲756,061	+49.55%	$47.17K
18	MILLENNIUM MANAGEMENT LLC	0001273087	2,127,779	0.87%	▲1,496,724	+237.18%	$43.98Mn
19	Sixth Street Partners Management Company, L.P.	0001812095	2,120,102	0.87%	▲2,120,102	0.00%	$43.82Mn
19	CHARLES SCHWAB INVESTMENT MANAGEMENT INC	0000884546	2,120,102	0.87%	▲52,172	+2.52%	$43.82Mn

Showing 1 to 20 of 465 holders