Amentum Holdings, Inc.

AMTMNYSE

$18.51-0.26 (-1.39% today)

Legend

Insider buy

Insider sell

Congress buy

Congress sell

Hedge Funds
bought vs soldGreener markers show more buyers; redder markers show more sellers.

Company share activityNet buybacksNo changeNet dilution

Marker size reflects transaction size.

Insider buy
Insider sell
Congress buy
Congress sell
Hedge Funds bought vs sold

Share activityNet buybacksNo changeNet dilution

Marker size reflects transaction size. Greener fund markers mean more buyers.

Insider Buy
Insider Sell
Congress Buy
Congress Sell
Hedge funds bought vs sold
BuybackNo changeNet dilution

Amentum Holdings, Inc. price and activity chart data

Showing the 1Y range: Oct 7, 2025 to Oct 7, 2026. Price (-26.7%). 0 insider or congressional trades plotted in this window as 0 markers; nearby trades of the same kind are grouped.

Transactions plotted on the price chart
Date	Category	Person	Role	Action	Amount	Change in holding

Largest institutional holders

13F · Q2 2026

Fund	% of company held	Value	% of portfolio	Quarterly activity
American Securities LLC	18.43%	$931M	24.79%	Not reported
Invesco Ltd.	10.21%	$516M	0.04%	Not reported
BlackRock, Inc.	7.33%	$370M	0.01%	Not reported
Primecap Management Co	5.03%	$254M	0.15%	Add 1.66%
Legacy Advisors, LLC	3.71%	$9.07M	0.85%	Add 0.02%
Vanguard Portfolio Management LLC	3.25%	$164M	0.01%	Not reported
Vanguard Capital Management LLC	2.75%	$139M	0.00%	Not reported
FMR LLC	2.32%	$117M	0.01%	Not reported
Dimensional Fund Advisors LP	2.27%	$114M	0.02%	Not reported
State Street Corp	2.11%	$106M	0.00%	Not reported
Frontier Capital Management Co LLC	1.70%	$85.7M	0.80%	Reduce 15.95%
Troluce Capital Advisors LLC	1.46%	$73.7M	7.59%	Add 256.54%
Geode Capital Management, LLC	1.11%	$56.2M	0.00%	Not reported
Goldman Sachs Group Inc	1.11%	$56.1M	0.00%	Not reported
Morgan Stanley	1.09%	$55M	0.00%	Not reported
MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.	0.95%	$47.9M	0.06%	Not reported
Thompson Siegel & Walmsley LLC	0.93%	$47.2M	0.85%	Add 49.55%
Millennium Management LLC	0.87%	$44M	0.02%	Not reported
Charles Schwab Investment Management Inc	0.87%	$43.8M	0.01%	Not reported
Thrivent Financial for Lutherans	0.86%	$43.5M	0.07%	Add 0.25%
Bank of America Corp	0.84%	$42.2M	0.00%	Not reported
Segra Capital Management, LLC	0.83%	$42.1M	8.50%	Add 26.36%
Verition Fund Management LLC	0.83%	$41.7M	0.21%	Not reported
Van Eck Associates Corp	0.81%	$41.1M	0.03%	Add 263.17%
Voya Investment Management LLC	0.81%	$40.8M	0.04%	Not reported
UBS Group AG	0.63%	$31.9M	0.00%	Not reported
Norges Bank	0.62%	$31.3M	0.00%	Not reported
Permian Investment Partners, LP	0.59%	$29.6M	3.25%	Reduce 8.55%
683 Capital Management, LLC	0.45%	$22.7M	1.12%	Add 41.94%
Loomis Sayles & Co L P	0.43%	$21.5M	0.03%	Reduce 3.59%
Qube Research & Technologies Ltd	0.42%	$21.4M	0.02%	Not reported
Northern Trust Corp	0.42%	$21.3M	0.00%	Not reported
Vanguard Fiduciary Trust Co	0.40%	$20M	0.00%	Not reported
Cacti Asset Management LLC	0.36%	$18.2M	0.91%	Not reported
Bank of New York Mellon Corp	0.36%	$18.2M	0.00%	Not reported
Russell Investments Group, Ltd.	0.34%	$17.4M	0.02%	Not reported
Avenir Corp	0.33%	$16.8M	2.04%	Not reported
Wells Fargo & Company	0.31%	$15.5M	0.00%	Not reported
Principal Financial Group Inc	0.30%	$15.3M	0.01%	Not reported
Ancora Advisors LLC	0.29%	$14.8M	0.29%	Not reported
Royce & Associates LP	0.29%	$14.4M	0.12%	Not reported
Citadel Advisors LLC	0.27%	$13.9M	0.00%	Not reported
Point72 Asset Management, L.P.	0.27%	$13.4M	0.01%	Not reported
AQR Capital Management LLC	0.25%	$12.4M	0.00%	Not reported
First Trust Advisors LP	0.22%	$11.3M	0.01%	Add 140.22%
Ruane, Cunniff & Goldfarb L.P.	0.22%	$11.1M	0.17%	Reduce 66.90%
Public Sector Pension Investment Board	0.22%	$10.9M	0.03%	Reduce 3.82%
Loews Corp	0.20%	$10.3M	0.08%	Not reported
First National Bank of Omaha	0.19%	$9.72M	0.27%	Not reported
Shapiro Capital Management LLC	0.19%	$9.84M	0.60%	New Not reported

50 of 425 holders

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