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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
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 $5.72T AUM 30.48% 1-Year Est. Return
Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $481B AUM 30.42% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
TD Asset Management
TD Asset Management Toronto, Ontario, Canada $123B AUM 34.51% 1-Year Est. Return
Fuller & Thaler Asset Management
Fuller & Thaler Asset Management San Mateo, California $29.7B AUM 43.33% 1-Year Est. Return
Marshall Wace
Marshall Wace London, United Kingdom $100B AUM 35.1% 1-Year Est. Return
American Century Companies
American Century Companies Kansas City, Missouri $194B AUM 35% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
BTW
Boston Trust Walden Boston, Massachusetts $13.1B AUM 24.63% 1-Year Est. Return

Magnetar Financial's AMPH Position: Q1 2026 in Review

Magnetar Financial opened a new position in Amphastar Pharmaceuticals (AMPH) in Q1 2026: 11,235 shares worth $220K. The stake represents ﹤0.01% of the portfolio and ranks #868 among its holdings. This is a return to the name: Magnetar Financial previously reported a position in AMPH as recently as Q2 2025.

Magnetar Financial first reported a position in AMPH in Q2 2025 and has held it in 2 quarters since. The position peaked at $306K in Q2 2025. 215 funds tracked by Wall St. Rank hold AMPH as of Q1 2026.

  • Magnetar Financial held 11,235 shares of Amphastar Pharmaceuticals worth $220K as of Q1 2026.
  • Amphastar Pharmaceuticals was a new Magnetar Financial position in Q1 2026.
  • Amphastar Pharmaceuticals made up ﹤0.01% of Magnetar Financial's portfolio in Q1 2026, its #868 holding.
  • Magnetar Financial first reported a position in Amphastar Pharmaceuticals in Q2 2025 and has held it in 2 quarters since.
  • Magnetar Financial's Amphastar Pharmaceuticals position peaked at $306K in Q2 2025.
  • 215 funds tracked by Wall St. Rank held Amphastar Pharmaceuticals as of Q1 2026.

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