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AMPH · Amphastar Pharmaceuticals, Inc.

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Market Cap
$936.26M
Shares
42.54M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 209
Total Value: $571,885,733
Total Shares: 28,310,032
Showing 1–100 of 212 holdings by value · page 1 of 3

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 209 13F filers · Δ vs Mar 31, 2026
Top Holder
18.4%
Sep 2023 → Jun 2026 · range 16.3% – 19.0%
+1.7 pts
Top 5
41.7%
Sep 2023 → Jun 2026 · range 37.4% – 48.9%
+4.3 pts
Top 10
58.3%
Sep 2023 → Jun 2026 · range 54.0% – 63.6%
+4.3 pts
HHI
578
Sep 2023 → Jun 2026 · range 495 – 682
Broadly held+83

Quarterly Activity

vs Mar 31, 2026
New
33
Increased
63
Decreased
76
Sold Out
39
Unchanged
37
Holder count: -6
Institutional value: -10.0%
Shares held: -12.7%

Top Buyers

vs Mar 31, 2026
Institution Added Now Holds Open

Top Sellers

vs Mar 31, 2026
Institution Sold Now Holds Open

Top New Positions

vs Mar 31, 2026
Institution Acquired Value (USD) Open

Top Sold-Out Positions

vs Mar 31, 2026
Institution Previously Held Last Value (USD) Open
Showing 100 of 212
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Holder Value (USD) % of 13F Shares Open
Key facts CIK 1297184 CUSIP 03209R103 13F (30d) 169 filings 167 filers Visit website Investor relations