Amentum Holdings
AMTM • XNYS
Amentum Holdings is a publicly traded company on XNYS, led by John E. Heller, with a market cap of $7.2B. As of Q3 2025, 80% of shares are held by 449 institutional investors, with AMERICAN SECURITIES LLC as the largest holder at 18.5%.
CEO of Amentum Holdings, Inc.John E. Heller
Market Cap$7.2B
Websiteamentum.com
Overview
Overview of institutional ownership in AMTM as of Q3 2025 with a market cap of $5.8B
All Institutions
- Institutions
- 449
- Value Held
- $4.6B
- Shares Held
- 193.5M
- Avg Position
- $10.3M
- Median Position
- $312.7K
Hedge Funds
- Hedge Funds
- 47
- Value Held
- $371.0M
- Shares Held
- 15.5M
- Avg Position
- $7.9M
- Median Position
- $3.0M
Ownership Breakdown
Based on market cap of $5.8B as of Q3 2025. Institutional (non-HF) excludes hedge funds to avoid double counting.
Biggest Investors
Institutions with the largest positions in AMTM as of Q3 2025
| Institution | Position Value |
|---|---|
 AMERICAN SECURITIES LLC Private Equity | $1.1B 100.00% of portfolio |
 Invesco Ltd. ETF Provider | $529.7M 0.08% of portfolio |
B BlackRock, Inc. Institution | $430.9M 0.01% of portfolio |
 VANGUARD GROUP INC Institution | $372.5M 0.01% of portfolio |
 PRIMECAP MANAGEMENT CO/CA/ Long Only Manager | $285.5M 0.22% of portfolio |
 STATE STREET CORP Institution | $163.7M 0.01% of portfolio |
 FMR LLC Institution | $149.3M 0.01% of portfolio |
 FRONTIER CAPITAL MANAGEMENT CO LLC Long Only Manager | $124.6M 1.12% of portfolio |
 Kovitz Investment Group Partners, LLC RIA/Wealth | $72.0M 0.28% of portfolio |
 THOMPSON SIEGEL & WALMSLEY LLC Long Only Manager | $65.4M 1.08% of portfolio |
Net Capital Flow
Institutional buying and selling activity for AMTM in Q3 2025
- Traded
- −$107.6M
- Buyers
- 186
- Sellers
- 234
- Total Bought
- +$347.5M
- Total Sold
- −$455.1M
- Avg Position
- $8.9M
Biggest Buyers
| Institution | Net Bought |
|---|---|
Invesco Ltd. ETF Provider | +$60.8M +2.5M shares |
FMR LLC Institution | +$39.8M +1.7M shares |
 Verition Fund Management LLC Hedge Fund•Multi-Strategy | +$25.0M +1.0M shares |
 Point72 Asset Management, L.P. Hedge Fund•Multi-Strategy | +$24.7M +1.0M shares |
M MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. Institution | +$16.8M +701.9K shares |
 GOLDMAN SACHS GROUP INC Institution | +$13.7M +573.7K shares |
 ING INVESTMENT MANAGEMENT LLC Insurance Manager | +$10.4M +433.4K shares |
 SEGRA CAPITAL MANAGEMENT, LLC Hedge Fund•Sector | +$10.0M +417.0K shares |
 TWO SIGMA INVESTMENTS LLC Hedge Fund•Multi-Strategy | +$9.2M +385.4K shares |
H Hyperion Capital Advisors LP Hedge Fund•Long/Short | +$8.8M +368.5K shares |
Biggest Sellers
| Institution | Net Sold |
|---|---|
 MILLENNIUM MANAGEMENT LLC Hedge Fund•Multi-Strategy | −$96.4M −4.0M shares |
 VAN ECK ASSOCIATES CORP ETF Provider | −$55.1M −2.3M shares |
 DISCOVERY CAPITAL MANAGEMENT, LLC / CT Hedge Fund•Global Macro | −$27.8M −1.2M shares |
B BlackRock, Inc. Institution | −$24.1M −1.0M shares |
VANGUARD GROUP INC Institution | −$23.5M −979.1K shares |
V Voss Capital LLC Institution | −$18.6M −775.0K shares |
 Kopernik Global Investors, LLC Hedge Fund•Long/Short | −$15.0M −636.2K shares |
 Engine Capital Management, LLC Hedge Fund•Event Driven | −$15.0M −635.3K shares |
 UBS Group AG Institution | −$12.8M −535.1K shares |
F FIL Ltd Institution | −$12.2M −508.2K shares |
Entry and Exit Activity
Institutions that initiated new positions or completely exited AMTM in Q3 2025
- New Positions
- 47
- New Value
- $51.5M
- Exited Positions
- 68
- Exited Value
- $68.3M
New Positions
| Institution | Position Value |
|---|---|
SEGRA CAPITAL MANAGEMENT, LLC Hedge Fund•Sector | $10.0M 417.0K shares |
 HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC Long Only Manager | $6.4M 268.1K shares |
 Trexquant Investment LP Hedge Fund•Quant | $6.1M 255.7K shares |
 Gotham Asset Management, LLC Hedge Fund•Long/Short | $5.9M 244.8K shares |
H HRT FINANCIAL LLC Institution | $4.5M 186.2K shares |
 Atom Investors LP Hedge Fund•Market Neutral | $3.5M 144.3K shares |
D DARK FOREST CAPITAL MANAGEMENT LP Pension/Endowment | $2.3M 95.9K shares |
S South Dakota Investment Council Institution | $1.5M 64.4K shares |
 SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC Hedge Fund•Distressed | $1.3M 54.3K shares |
 Blackstone Group L.P. Institution | $1.2M 49.1K shares |
Exited Positions
| Institution | Previous Position |
|---|---|
Kopernik Global Investors, LLC Hedge Fund•Long/Short | $15.0M 636.2K shares |
Engine Capital Management, LLC Hedge Fund•Event Driven | $15.0M 635.3K shares |
 LOEWS CORP Institution | $11.1M 470.0K shares |
 Arosa Capital Management LP Hedge Fund•Multi-Strategy | $6.0M 252.5K shares |
Y Y-Intercept Ltd Institution | $4.7M 198.7K shares |
N NOMURA HOLDINGS INC Institution | $2.6M 108.2K shares |
 RFG Advisory Group, LLC RIA/Wealth | $2.4M 102.2K shares |
 Marshall Wace LLP Institution | $1.8M 74.8K shares |
 Fortress Investment Group LLC RIA/Wealth | $899.7K 38.1K shares |
$832.6K 35.3K shares |
Options Activity
Institutions with the largest Call and Put options positions in AMTM as of Q3 2025
- Call Positions
- 14
- Call Value
- $18.8M
- Put Positions
- 11
- Put Value
- $14.2M
Call Positions
| Institution | Position Value |
|---|---|
 SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity | $7.3M 3.1K contracts |
 Walleye Trading LLC RIA/Wealth | $4.0M 1.7K contracts |
 CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy | $2.5M 1.0K contracts |
J JANE STREET GROUP, LLC Institution | $2.3M 943.2 contracts |
W WOLVERINE TRADING, LLC Institution | $1.2M 532.0 contracts |
 TUDOR INVESTMENT CORP ET AL Hedge Fund•Multi-Strategy | $445.5K 186.0 contracts |
 CAPITAL FUND MANAGEMENT S.A. Hedge Fund•Quant Macro | $400.0K 167.0 contracts |
 Walleye Trading Advisors, LLC Hedge Fund•Multi-Strategy | $354.5K 148.0 contracts |
GOLDMAN SACHS GROUP INC Institution | $289.4K 120.8 contracts |
P PEAK6 LLC Institution | - - contracts |
Put Positions
| Institution | Position Value |
|---|---|
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity | $6.9M 2.9K contracts |
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy | $4.8M 2.0K contracts |
J JANE STREET GROUP, LLC Institution | $637.1K 266.0 contracts |
Walleye Trading LLC RIA/Wealth | $550.9K 230.0 contracts |
W WOLVERINE TRADING, LLC Institution | $527.1K 231.0 contracts |
GOLDMAN SACHS GROUP INC Institution | $289.4K 120.8 contracts |
CAPITAL FUND MANAGEMENT S.A. Hedge Fund•Quant Macro | $270.6K 113.0 contracts |
Walleye Trading Advisors, LLC Hedge Fund•Multi-Strategy | $198.8K 83.0 contracts |
S SIG BROKERAGE, LP Institution | - - contracts |
P PEAK6 LLC Institution | - - contracts |
Most Committed Institutions
Institutions with AMTM as the highest % of their portfolio as of Q3 2025
| Institution | Portfolio Weight |
|---|---|
AMERICAN SECURITIES LLC Private Equity | 100.00% $1.1B |
 BRIGHTLINE CAPITAL MANAGEMENT, LLC Hedge Fund•Value | 11.78% $28.7M |
SEGRA CAPITAL MANAGEMENT, LLC Hedge Fund•Sector | 11.55% $10.0M |
 Arvin Capital Management LP Hedge Fund•Long/Short | 9.07% $39.2M |
A AWH Capital, L.P. Hedge Fund•Long/Short | 5.88% $5.6M |
H Hyperion Capital Advisors LP Hedge Fund•Long/Short | 5.38% $10.1M |
G GRIZZLYROCK CAPITAL, LLC Hedge Fund•Value | 5.27% $6.8M |
L Lingohr & Partner Asset Management GmbH Institution | 4.82% $4.2M |
6 683 Capital Management, LLC Hedge Fund•Long/Short | 2.88% $30.5M |
S Soviero Asset Management, LP Hedge Fund•Long/Short | 2.29% $3.7M |
Hedge Fund Spotlight
Discover hedge funds investing in AMTM
ISAM Funds Ltd
Hedge Fund • Quant
Portfolio ManagerRoy Sher
- Portfolio Value
- $489.3M
- Positions
- 601
- Last Reported
- Q3 2025
Sector Allocation
Position in Amentum Holdings
- Market Value
- $259.8K
- Shares Held
- 10.8K
- Portfolio Weight
- 0.05%
- Owned Since
- 2025-Q3
| Top Holding | Sector | Market Value | Weight |
|---|---|---|---|
Drug Manufacturers - General Healthcare | $4.9M | 1.00% | |
Insurance - Property & Casualty Financial Services | $4.9M | 1.00% | |
Drug Manufacturers - General Healthcare | $4.9M | 0.99% |
