Amentum Holdings Inc. (AMTM)
Who owns Amentum Holdings Inc. (AMTM)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 62.4% of the shares are freely tradable; institutional investors hold 107.7%.
Ownership Structure
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| AMERICAN SECURITIES LLC | 18.43 | 45,026,743 | +0.0 | 03/31/2026 |
| Amvescap Plc. | 8.79 | 21,473,778 | -1.6 | 03/31/2026 |
| BlackRock Inc | 7.30 | 17,841,283 | +2.2 | 03/31/2026 |
| Vanguard Group Inc | 6.31 | 15,411,745 | -0.9 | 12/31/2025 |
| PRIMECAP Management Company | 4.95 | 12,085,294 | -0.3 | 03/31/2026 |
| Legacy Advisors, LLC | 3.71 | 9,064,278 | -7.6 | 03/31/2026 |
| Vanguard Portfolio Management, LLC | 3.21 | 7,852,951 | +0.0 | 03/31/2026 |
| Vanguard Capital Management, LLC | 2.72 | 6,650,879 | +0.0 | 03/31/2026 |
| FMR Inc | 2.28 | 5,578,386 | -16.8 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| iShares Core S&P Small-Cap ETF | 3.82 | 9,331,307 | +0.0 | 05/29/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Data as of: July 31, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.