AMENTUM HOLDINGS INC (AMTM): Ownership & Insider Activity
Hedge funds and institutional managers reporting a position in AMTM · Industrials. Based on the most recent 13F filing from each holder, sourced from SEC EDGAR.
Reported Holders
23
13F filers
Aggregate Value
$465.3M
Across holders
Last Price
$20.06
2026-08-24
Sector
Industrials
GICS
Quarterly fund activity16 increased7 reduced2 exited
Full exits: MAVERICK CAPITAL LTD, Lighthouse Investment Partners, LLC
| Manager⇅ | Type⇅ | Shares⇅ | Market Value▼ | % of Total⇅ | % of Portfolio⇅ | Action⇅ | QoQ Change⇅ | Quarter⇅ |
|---|---|---|---|---|---|---|---|---|
| PRIMECAP MANAGEMENT CO/CA/ CIK 0000763212 | Institutional Manager | 12.29M | $253.9M | 54.6% | 0.2% | Added | +$4.1M | Q2 2026 |
| MILLENNIUM MANAGEMENT LLC CIK 0001273087 | Hedge Fund | 2.13M | $44.0M | 9.5% | 0.0% | Added | +$30.9M | Q2 2026 |
| Verition Fund Management LLC CIK 0001454027 | Hedge Fund | 2.02M | $41.7M | 9.0% | 0.2% | Added | +$14.9M | Q2 2026 |
| Qube Research & Technologies Ltd CIK 0001729829 | Hedge Fund | 1.03M | $21.4M | 4.6% | 0.0% | Added | +$19.8M | Q2 2026 |
| Ancora Advisors, LLC CIK 0001446114 | Hedge Fund | 716K | $14.8M | 3.2% | 0.3% | Added | $-13.7M | Q2 2026 |
| CITADEL ADVISORS LLC CIK 0001423053 | Hedge Fund | 671K | $13.9M | 3.0% | 0.0% | Added | +$10.1M | Q2 2026 |
| Point72 Asset Management, L.P. CIK 0001603466 | Hedge Fund | 650K | $13.4M | 2.9% | 0.0% | Reduced | $-20.3M | Q2 2026 |
| AQR CAPITAL MANAGEMENT LLC CIK 0001167557 | Hedge Fund | 602K | $12.4M | 2.7% | 0.0% | Added | +$11.3M | Q2 2026 |
| Ruane, Cunniff & Goldfarb L.P. CIK 0001720792 | Hedge Fund | 537K | $11.1M | 2.4% | 0.2% | Reduced | $-22.4M | Q2 2026 |
| MOORE CAPITAL MANAGEMENT, LP CIK 0001448574 | Hedge Fund | 365K | $7.5M | 1.6% | 0.1% | Reduced | $-10.5M | Q2 2026 |
Added
Institutional Manager
$253.9M· 54.6% of total· 0.2% port· 12.29M sh· +$4.1M QoQ· Q2 2026
Added
Hedge Fund
$44.0M· 9.5% of total· 0.0% port· 2.13M sh· +$30.9M QoQ· Q2 2026
Added
Hedge Fund
$41.7M· 9.0% of total· 0.2% port· 2.02M sh· +$14.9M QoQ· Q2 2026
Added
Hedge Fund
$21.4M· 4.6% of total· 0.0% port· 1.03M sh· +$19.8M QoQ· Q2 2026
Added
Hedge Fund
$14.8M· 3.2% of total· 0.3% port· 716K sh· $-13.7M QoQ· Q2 2026
Added
Hedge Fund
$13.9M· 3.0% of total· 0.0% port· 671K sh· +$10.1M QoQ· Q2 2026
Reduced
Hedge Fund
$13.4M· 2.9% of total· 0.0% port· 650K sh· $-20.3M QoQ· Q2 2026
Added
Hedge Fund
$12.4M· 2.7% of total· 0.0% port· 602K sh· +$11.3M QoQ· Q2 2026
Reduced
Hedge Fund
$11.1M· 2.4% of total· 0.2% port· 537K sh· $-22.4M QoQ· Q2 2026
Reduced
Hedge Fund
$7.5M· 1.6% of total· 0.1% port· 365K sh· $-10.5M QoQ· Q2 2026
Reduced
Hedge Fund
$5.9M· 1.3% of total· 0.0% port· 284K sh· +$5.7M QoQ· Q2 2026
Added
Hedge Fund
$4.7M· 1.0% of total· 0.0% port· 226K sh· — QoQ· Q2 2026
Added
Hedge Fund
$4.0M· 0.9% of total· 0.0% port· 191K sh· +$2.9M QoQ· Q2 2026
Added
Hedge Fund
$3.5M· 0.7% of total· 0.0% port· 167K sh· +$1.9M QoQ· Q2 2026
Reduced
Hedge Fund
$3.2M· 0.7% of total· 0.0% port· 156K sh· $-7.5M QoQ· Q2 2026
Added
Family Office
$2.4M· 0.5% of total· 0.0% port· 118K sh· +$221K QoQ· Q2 2026
Added
Institutional Manager
$2.0M· 0.4% of total· 0.0% port· 97K sh· +$37K QoQ· Q2 2026
Reduced
Hedge Fund
$1.8M· 0.4% of total· 0.0% port· 89K sh· $-706K QoQ· Q2 2026
Added
Hedge Fund
$1.8M· 0.4% of total· 0.0% port· 85K sh· +$1.4M QoQ· Q2 2026
Added
Hedge Fund
$976K· 0.2% of total· 0.0% port· 47K sh· +$624K QoQ· Q2 2026
Added
Institutional Manager
$446K· 0.1% of total· 0.0% port· 22K sh· — QoQ· Q2 2026
Added
Hedge Fund
$286K· 0.1% of total· 0.0% port· 14K sh· +$46K QoQ· Q2 2026
Reduced
Hedge Fund
$85K· 0.0% of total· 0.0% port· 4K sh· $-237K QoQ· Q2 2026
1–10 of 23
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