Amentum Holdings AMTM Institutional Ownership

NYSE AMTM

$21.27 +1.13 (+5.58%)

As of: Oct 22, 2026 · 3:59 PM EDT

Institutions by Trading Activity

463 Institutions

Increased 210 45.4%

Unchanged 99 21.4%

Reduced 154 33.3%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

89.67%

▲+3.17 pp QoQ

Shares Held by Institutions

218.87Mn

of 244.09Mn outstanding

▲+3.70% QoQ

Shares Outstanding

244.09Mn

25.22Mn held outside 13F filers

Institutional Investors

463

filed 13F for Jun 2026

▼-21 vs prior quarter

Net Shares Added (QoQ)

+7.82Mn

accumulated since last quarter

Value of Holdings

$4.41Bn

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

Updated Oct 11, 2026

Amentum Holdings, Inc. (NYSE:AMTM) counted 463 institutional investors among its 13F-reported shareholders for the quarter ended June 30, 2026.

These investors held 89.67% of outstanding shares in Q2 2026, up from 86.50% the quarter before.
Total shares held in AMTM rose 3.70% from Q1 2026; the number of holders rose 0.87% from Q2 2025.
Among the 463 holders of Amentum Holdings, 210 added to their positions, 154 reduced their stakes and 99 left their positions unchanged.
The aggregate institutional position in Amentum Holdings was 218.87Mn shares at the end of Q2 2026, up 7.82Mn from the prior quarter and up 21.04Mn from a year earlier.
American Securities LLC led 13F holders of AMTM with 45.03Mn shares as of June 30, 2026, or 18.45% of shares outstanding.
The biggest increases in AMTM positions during Q2 2026 came from Invesco Ltd. (+3.48Mn shares), Troluce Capital Advisors LLC (+2.57Mn shares), Dimensional Fund Advisors LP (+1.75Mn shares), Goldman Sachs Group Inc (+1.58Mn shares) and Millennium Management LLC (+1.5Mn shares).
On the other side, among holders that kept a position in Amentum Holdings, the largest reductions in Q2 2026 came from Focus Partners Wealth (-2.47Mn shares), Arvin Capital Management LP (-1.65Mn shares), Ruane, Cunniff & Goldfarb L.P. (-1.09Mn shares), Point72 Asset Management, L.P. (-980.58K shares) and Frontier Capital Management Co LLC (-786.24K shares).
Per Business Quant, the top 10 investors in AMTM for the quarter ended June 30, 2026 were American Securities LLC (45.03Mn shares), Invesco Ltd. (24.95Mn shares), BlackRock, Inc. (17.91Mn shares), Primecap Management Co (12.29Mn shares), Legacy Advisors, LLC (9.07Mn shares), Vanguard Portfolio Management LLC (7.95Mn shares), Vanguard Capital Management LLC (6.71Mn shares), FMR LLC (5.68Mn shares), Dimensional Fund Advisors LP (5.54Mn shares) and State Street Corp (5.15Mn shares).

Form 13F Holdings

464 Institutional Holders

Report period 30 Jun, 2026

Total shares held 218.87Mn

Of outstanding 89.67%

#	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	10.22%	▲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	5.03%	▲200,210	+1.66%	$253.94Mn
5	Legacy Advisors, LLC	0001720969	9,065,677	3.71%	▲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	0.93%	▲756,061	+49.55%	$47.17K
18	MILLENNIUM MANAGEMENT LLC	0001273087	2,127,779	0.87%	▲1,496,724	+237.18%	$43.98Mn
19	CHARLES SCHWAB INVESTMENT MANAGEMENT INC	0000884546	2,120,102	0.87%	▲52,172	+2.52%	$43.82Mn
20	THRIVENT FINANCIAL FOR LUTHERANS	0000314984	2,105,802	0.86%	▲5,345	+0.25%	$43.53K

Showing 1 to 20 of 464 holders