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Magnetar Financial’s Amphastar Pharmaceuticals AMPH Stock Holding History

Magnetar Financial’s Portfolio AMPH Stock Details AMPH Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$220K Sell
10,906
-329
-3% -$6.64K ﹤0.01% 910
2026
Q1 		$220K Buy
+11,235
New +$275K ﹤0.01% 868
2025
Q3 		– Sell
-13,337
Closed -$306K – 881
2025
Q2 		$306K Buy
+13,337
New +$331K ﹤0.01% 696

Other funds holding AMPH

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $552B AUM 44.19% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.38T AUM 44.17% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
American Century Companies
American Century Companies Kansas City, Missouri $226B AUM 44.75% 1-Year Est. Return
Marshall Wace
Marshall Wace London, United Kingdom $127B AUM 46.06% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
Fuller & Thaler Asset Management
Fuller & Thaler Asset Management San Mateo, California $36.7B AUM 74.15% 1-Year Est. Return
D.E. Shaw & Co
D.E. Shaw & Co New York $210B AUM 57.28% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

Magnetar Financial's AMPH Position: Q2 2026 in Review

Magnetar Financial reduced its Amphastar Pharmaceuticals (AMPH) stake by 2.9% in Q2 2026, selling an estimated $6.64K and leaving 10,906 shares worth $220K. The position accounts for ﹤0.01% of the portfolio, ranked #910.

Magnetar Financial first reported a position in AMPH in Q2 2025 and has held it in 3 quarters since. The position peaked at $306K in Q2 2025. 211 funds tracked by Wall St. Rank hold AMPH as of Q2 2026.

  • Magnetar Financial held 10,906 shares of Amphastar Pharmaceuticals worth $220K as of Q2 2026.
  • Magnetar Financial sold 329 Amphastar Pharmaceuticals shares in Q2 2026, an estimated $6.64K.
  • Amphastar Pharmaceuticals made up ﹤0.01% of Magnetar Financial's portfolio in Q2 2026, its #910 holding.
  • Magnetar Financial first reported a position in Amphastar Pharmaceuticals in Q2 2025 and has held it in 3 quarters since.
  • Magnetar Financial's Amphastar Pharmaceuticals position peaked at $306K in Q2 2025.
  • 211 funds tracked by Wall St. Rank held Amphastar Pharmaceuticals as of Q2 2026.

Based on Magnetar Financial's 13F filing for Q2 2026, filed 14 Aug 2026.