AMPHASTAR PHARMACEUTICALS IN (AMPH) Stock Institutional Trading Activity


AMPHASTAR PHARMACEUTICALS IN (AMPH) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Renaissance Technologies LLC. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q4 2025Renaissance Technologies LLCSell-42,200544,700$14,587,066
Q3 2025Renaissance Technologies LLCBuy10,400586,900$15,640,885
Q2 2025Renaissance Technologies LLCBuy81,500576,500$13,236,440
Q1 2025Renaissance Technologies LLCSell-30,500495,000$14,350,050
Q4 2024Renaissance Technologies LLCBuy36,100525,500$19,511,815
Q3 2024Renaissance Technologies LLCSell-48,300489,400$23,750,582
Q2 2024Renaissance Technologies LLCSell-61,400537,700$21,508,000
Q1 2024Renaissance Technologies LLCSell-42,800599,100$26,306
Q4 2023Renaissance Technologies LLCBuy38,800641,900$39,702
Q3 2023Renaissance Technologies LLCBuy110,517603,100$27,737
Q2 2023Renaissance Technologies LLCSell-4,217492,583$28,309
Q1 2023Renaissance Technologies LLCBuy49,400496,800$18,630
Q4 2022Renaissance Technologies LLCBuy13,600447,400$12,536
Q3 2022Renaissance Technologies LLCBuy26,900433,800$12,190
Q2 2022Renaissance Technologies LLCBuy98,200406,900$14,156
Q1 2022Renaissance Technologies LLCBuy18,900308,700$11,082
Q4 2021Renaissance Technologies LLCBuy14,100289,800$6,749
Q3 2021Renaissance Technologies LLCBuy28,600275,700$5,241
Q2 2021Renaissance Technologies LLCBuy21,500247,100$4,982
Q1 2021Renaissance Technologies LLCSell-87,000225,600$4,133
Q4 2020Renaissance Technologies LLCSell-65,700312,600$6,286
Q3 2020Renaissance Technologies LLCSell-133,000378,300$7,093
Q2 2020Renaissance Technologies LLCSell-227,300511,300$11,484
Q1 2020Renaissance Technologies LLCSell-94,400738,600$10,961
Q4 2019Renaissance Technologies LLCBuy102,300833,000$16,069
Q3 2019Renaissance Technologies LLCBuy142,700730,700$14,490
Q2 2019Renaissance Technologies LLCBuy146,400588,000$12,413
Q1 2019Renaissance Technologies LLCBuy131,500441,600$9,022
Q4 2018Renaissance Technologies LLCBuy124,000310,100$6,171
Q3 2018Renaissance Technologies LLCBuy134,500186,100$3,581

Frequently asked questions about AMPH activity

  • Which institutional owners are buying AMPH?

    Institutional owners buying AMPH include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in AMPH activity?

    "Buy" means an investor increased their reported position in AMPH compared to the prior reporting period. This reflects growing exposure to AMPHASTAR PHARMACEUTICALS IN (AMPH) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in AMPH increasing?

    Institutional interest in AMPH can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.