AMTM · Insider Trading
Amentum Holdings, Inc.
Every open-market purchase and sale reported by AMTM officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-09-17 | Christopher M.T. Thompson | Director | G | −4,250 | — |
| 2026-05-07 | Stephen A Arnette | Chief Operating Officer | MIXED | +10,295 | −$82.49K |
| 2026-05-07 | Jill L Bruning | Chief Technology Officer | MIXED | +6,341 | −$67.97K |
| 2026-05-07 | Travis Barton Johnson | Chief Financial Officer | MIXED | +9,512 | −$101.97K |
| 2026-05-07 | Sean Thomas Mullen | Chief Growth Officer | MIXED | +6,310 | −$68.75K |
| 2026-05-07 | John E. Heller | Chief Executive Officer | MIXED | +9,961 | −$203.70K |
| 2026-03-05 | Jill L Bruning | Chief Technology Officer | G | −30,000 | — |
| 2026-03-04 | Stephen A Arnette | Chief Operating Officer | MIXED | +2,058 | −$23.02K |
| 2026-02-18 | Michele T St. Mary | Chief Legal Officer & GC | MIXED | +4,772 | −$69.36K |
| 2026-02-10 | Steven J. Demetriou | Executive Chair | — | — | — |
| 2026-02-10 | John C. Vollmer | Director | MIXED | +16,626 | — |
| 2026-02-10 | Christopher M.T. Thompson | Director | A | +5,062 | — |
| 2026-02-10 | Barbara Loughran | Director | A | +5,062 | — |
| 2026-02-10 | Ralph E Eberhart | Director | MIXED | +16,626 | — |
| 2026-02-10 | Vincent K Brooks | Director | MIXED | +16,626 | — |
| 2026-02-10 | Sandra E. Rowland | Director | MIXED | +16,626 | — |
| 2026-02-10 | Susan Leslie Ireland | Director | A | +5,062 | — |
| 2026-01-29 | John E. Heller | Chief Executive Officer | MIXED | +32,211 | −$705.92K |
| 2025-12-19 | John E. Heller | Chief Executive Officer | — | — | — |
| 2025-12-19 | Stephen A Arnette | Chief Operating Officer | — | — | — |
| 2025-12-19 | Jill L Bruning | Chief Technology Officer | — | — | — |
| 2025-12-19 | Sean Thomas Mullen | Chief Growth Officer | MIXED | +5,104 | −$120.24K |
| 2025-12-09 | Darren Burton | Chief People Officer | MIXED | +1,329 | −$40.20K |
| 2025-11-19 | Steven J. Demetriou | Executive Chair | MIXED | +137,674 | −$366.98K |
| 2025-11-19 | Stephen A Arnette | Chief Operating Officer | MIXED | +47,660 | −$6.17K |
| 2025-11-19 | Michele T St. Mary | Chief Legal Officer & GC | A | +22,271 | — |
| 2025-11-19 | Travis Barton Johnson | Chief Financial Officer | A | +100,220 | — |
| 2025-11-19 | Darren Burton | Chief People Officer | A | +22,271 | — |
| 2025-11-19 | Jill L Bruning | Chief Technology Officer | A | +17,817 | — |
| 2025-11-19 | John E. Heller | Chief Executive Officer | A | +155,897 | — |
| 2025-11-19 | Sean Thomas Mullen | Chief Growth Officer | A | +17,817 | — |
| 2025-11-18 | Stephen A Arnette | Chief Operating Officer | MIXED | +14,437 | −$102.65K |
| 2025-11-10 | Stephen A Arnette | Chief Operating Officer | MIXED | +9,608 | −$67.40K |
| 2025-11-10 | Steven J. Demetriou | Executive Chair | MIXED | +61,909 | −$627.94K |
| 2025-11-10 | Sean Thomas Mullen | Chief Growth Officer | MIXED | +3,217 | −$35.32K |
| 2025-11-10 | John E. Heller | Chief Executive Officer | MIXED | +21,749 | −$389.34K |
| 2025-11-10 | Jill L Bruning | Chief Technology Officer | MIXED | +3,381 | −$31.75K |
| 2025-11-10 | Travis Barton Johnson | Chief Financial Officer | MIXED | +8,455 | −$79.36K |
| 2025-05-12 | Amentum Joint Venture LP | Director | J | −2,433,022 | — |
| 2025-05-12 | LG GP Holding IV LLC | 10%+ Owner | J | +1,132,839 | — |
| 2025-05-12 | Alan E Goldberg | Director | J | +1,132,839 | — |
| 2025-05-12 | Lindsay Goldberg Employee Co-Inv. IV L.P. | 10%+ Owner | J | +1,132,839 | — |
| 2025-04-10 | Christopher M.T. Thompson | Director | A | +11,564 deriv. | — |
| 2025-04-10 | Sandra E. Rowland | Director | A | +11,564 deriv. | — |
| 2025-04-10 | Susan Leslie Ireland | Director | A | +11,564 deriv. | — |
| 2025-04-10 | Barbara Loughran | Director | A | +11,564 deriv. | — |
| 2025-04-10 | Ralph E Eberhart | Director | A | +11,564 deriv. | — |
| 2025-04-10 | Vincent K Brooks | Director | A | +11,564 deriv. | — |
| 2025-04-10 | John C. Vollmer | Director | A | +11,564 deriv. | — |
| 2025-04-08 | Amentum Joint Venture GP LLC | Director | A | +2,433,022 | — |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| Alan E Goldberg | Director | 45,026,743 | $1.01B |
| LG GP Holding IV LLC | 10%+ Owner | 45,026,743 | $1.01B |
| Lindsay Goldberg Employee Co-Inv. IV L.P. | 10%+ Owner | 45,026,743 | $1.01B |
| Amentum Joint Venture GP LLC | Director | 2,433,022 | $54.82M |
| Steven J. Demetriou | Executive Chair | 861,218 | $19.40M |
| John C. Vollmer | Director | 424,780 | $9.57M |
| John E. Heller | Chief Executive Officer | 384,203 | $8.66M |
| Jill L Bruning | Chief Technology Officer | 200,188 | $4.51M |
| Travis Barton Johnson | Chief Financial Officer | 118,187 | $2.66M |
| Stephen A Arnette | Chief Operating Officer | 109,966 | $2.48M |
| Ralph E Eberhart | Director | 48,120 | $1.08M |
| Sean Thomas Mullen | Chief Growth Officer | 35,210 | $793.28K |
| Vincent K Brooks | Director | 27,462 | $618.72K |
| Michele T St. Mary | Chief Legal Officer & GC | 27,043 | $609.28K |
| Darren Burton | Chief People Officer | 23,600 | $531.71K |
| Christopher M.T. Thompson | Director | 19,062 | $429.47K |
| Sandra E. Rowland | Director | 15,011 | $338.20K |
| Barbara Loughran | Director | 9,662 | $217.68K |
| Susan Leslie Ireland | Director | 8,509 | $191.71K |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the AMTM quote page; the site-wide leaderboard is on the insider transactions hub.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.