Amentum Holdings, Inc.
AMTM- Exchange
- NYSE
- Industry
- Services-Business Services, NEC
- SEC CIK
- 0002011286
No open-market purchases or sales by Amentum Holdings, Inc. insiders were filed in the last 90 days; 464 institutions reported holding it in 13F filings for Q2 2026, worth $4.34B in total; Soros Fund Management is the only superinvestor holding it.
13F holders, Q3 2026
Institutional positions in Amentum Holdings, Inc. as of Sep 30, 2026. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works
Q3 2026 data is still coming in (13F filing deadline: Nov 16, 2026), so these numbers are incomplete.
- Institutional holders
- 4
- 0 vs. Q2 2026
- Shares held
- 883.2K
- −6.51K (−0.7%) vs. Q2 2026
- Total value
- $16.0M
- −$2.36M (−12.8%) vs. Q2 2026
- New holders
- 0
- 2 more added
- Sold out
- 0
- 1 more reduced
460 institutions that held it in Q2 2026 haven't filed for Q3 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q2 2026: new holders, sold out and not filed yet
Holders and value by quarter
Institutions reporting AMTM on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.
| Quarter | Holders | Value |
|---|---|---|
| Q2 2026 | 464 | $4.34B |
| Q1 2026 | 486 | $5.28B |
| Q4 2025 | 483 | $5.64B |
| Q3 2025 | 462 | $4.63B |
| Q2 2025 | 461 | $4.73B |
| Q1 2025 | 418 | $3.49B |
| Q4 2024 | 451 | $3.48B |
| Q3 2024 | 492 | $3.23B |
| Q2 2024 | 0 | $0 |
| Q1 2024 | 0 | $0 |
| Q4 2023 | 0 | $0 |
| Q3 2023 | 0 | $0 |
| Q2 2023 | 0 | $0 |
| Q1 2023 | 0 | $0 |
| Q4 2022 | 0 | $0 |
| Q3 2022 | 0 | $0 |
| Q2 2022 | 0 | $0 |
| Q1 2022 | 0 | $0 |
| Q4 2021 | 0 | $0 |
| Q3 2021 | 0 | $0 |
| Q2 2021 | 0 | $0 |
| Q1 2021 | 0 | $0 |
Institutions, Q3 2026
Shares, value and share of portfolio for each institution holding Amentum Holdings, Inc.; share changes are against Q2 2026.