MF
AMTM

Magnetar Financial’s Amentum Holdings AMTM Stock Holding History

Magnetar Financial’s Portfolio AMTM Stock Details AMTM Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		– Sell
-20,875
Closed -$605K – 1452
2025
Q4 		$605K Buy
+20,875
New +$534K 0.01% 527
2024
Q4 		– Sell
-10,073
Closed -$325K – 815
2024
Q3 		$325K Buy
+10,073
New +$287K 0.01% 395

Other funds holding AMTM

AS
American Securities New York $3.93B AUM 52.22% 1-Year Est. Return
Invesco
Invesco Atlanta, Georgia $1.02T AUM 30.18% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Primecap Management
Primecap Management Pasadena, California $127B AUM 44.11% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
FCM
Frontier Capital Management Boston, Massachusetts $9.73B AUM 55.65% 1-Year Est. Return
Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $481B AUM 30.42% 1-Year Est. Return

Magnetar Financial's AMTM Position: Q1 2026 in Review

Magnetar Financial sold out of Amentum Holdings (AMTM) in Q1 2026, closing a stake of 20,875 shares — an estimated $605K sold.

Magnetar Financial first reported a position in AMTM in Q3 2024 and held it in 2 quarters. The position peaked at $605K in Q4 2025. 486 funds tracked by Wall St. Rank hold AMTM as of Q1 2026.

  • Magnetar Financial reported no remaining Amentum Holdings position as of Q1 2026 after selling out during the quarter.
  • Magnetar Financial sold 20,875 Amentum Holdings shares in Q1 2026, an estimated $605K.
  • Magnetar Financial first reported a position in Amentum Holdings in Q3 2024 and held it in 2 quarters.
  • Magnetar Financial's Amentum Holdings position peaked at $605K in Q4 2025.
  • 486 funds tracked by Wall St. Rank held Amentum Holdings as of Q1 2026.

Based on Magnetar Financial's 13F filing for Q1 2026, filed 13 May 2026.