$AMTM

$21.74 -$0.33 (1.5%) Live

$AMTM Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 244.5M shares outstanding

Who owns AMTM?

By type of holder

Institutions 89.2% Insiders 10.8% Everyone else 0.0%

Concentration Top 10 holders own 180.0%

American Securities LLC 18.4% · ASP Manager Corp. 18.0%

Institutional ownership

89.2%

+2.9 pts vs last qtr

Institutional holders

460

-27 vs last qtr

Net shares bought

+7.1M

by institutions in Q2 2026

New / sold out

58 / 85

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

Invesco Ltd. +3.5M
Troluce Capital Advisors LLC +2.6M

Biggest sellers in Q2 2026

Focus Partners Wealth −2.5M
Arvin Capital Management LP −1.7M

Who is planning to sell?

No insider has filed a notice of proposed sale (Form 144) for Amentum Holdings, Inc. in the last 12 months.

Is your stake being diluted?

Diluted share count, FY2022–FY2025

+171.1%

+39.44% a year

Each share's claim on the business

−63.1%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

— vs $45M

over 4 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years0% 3–5 years0% 1–3 years87% Under 1 year13%

Quarterly turnover

10.6%

of institutional shares changed hands

Top 10 managers, median time held

1.8 years

Super Investors

Investment managers reporting AMTM on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
AS American Securities LLC 13D · 18.0%	45.0M	18.42%	Unchanged	2024	24.8%
Shares held by quarter Peak holding45.0M (Q2'25) Change over 8 quarters+45.0M Share of the company18.420% Disclosed stake13D · 18.0% American Securities LLC's full portfolio →
I Invesco Ltd.	25.0M	10.21%	+3.5M (+16.2%)	2024	0.0%
Shares held by quarter Peak holding25.0M (Q2'26) Change over 8 quarters+17.2M Share of the company10.210% Invesco Ltd.'s full portfolio →

American Securities LLC

13D · 18.0%

45.0M

% of company

18.42%

Change vs last qtr

Unchanged

Held since

2024

Invesco Ltd.

25.0M

% of company

10.21%

Change vs last qtr

+3.5M (+16.2%)

Held since

2024

28 more super investors behind a free account

See every manager holding Amentum Holdings, Inc., how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting AMTM on Form N-PORT; together they hold 31.4% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
IC iShares Core S&P Small-Cap ETF iShares Trust	$192M	9.3M	3.79%	0.17%	June 30, 2026
VP Vanguard Primecap Core Fund Vanguard Fenway Funds	$114M	5.5M	2.26%	0.63%	June 30, 2026

iShares Core S&P Small-Cap ETF

iShares Trust

Position value

$192M

% of company

3.79%

% of the fund

0.17%

As of

June 30, 2026

Vanguard Primecap Core Fund

Vanguard Fenway Funds

Position value

$114M

% of company

2.26%

% of the fund

0.63%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding Amentum Holdings, Inc. and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
AM ASP Manager Corp. 5%+ holder 13D · 18.0%	43.9M	17.95%	—	—	—	—
This holder reports through Schedule 13D/G, not a quarterly 13F. Share of the company17.950% Disclosed stake13D · 18.0% View the 13D/G filing →
AE Alan E. Goldberg 5%+ holder 13D · 18.0%	43.9M	17.95%	—	—	—	—
This holder reports through Schedule 13D/G, not a quarterly 13F. Share of the company17.950% Disclosed stake13D · 18.0% View the 13D/G filing →

ASP Manager Corp.

5%+ holder13D · 18.0%

43.9M

% of company

17.95%

Change vs last qtr

—

Held since

—

Alan E. Goldberg

5%+ holder13D · 18.0%

43.9M

% of company

17.95%

Change vs last qtr

—

Held since

—

31 more holders behind a free account

See every insider and 5%+ holder of Amentum Holdings, Inc..

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