Institutional Ownership
Amphastar Pharmaceuticals In
CUSIP 03209R103COMAMPHQ1 2026
13D / 13G Filings
25
Schedule 13D/13G on record
Beneficial Filers
6
Distinct reporting persons
Largest Stake
26.2%
Max % of class reported
Institutional Holders
207
13F filers (latest quarter)
Beneficial Owners — Schedule 13D / 13G
25 filings · latest Oct 17, 2025
| # | Filed | Reporting Person | Form | % of Class | Shares | Filing |
|---|---|---|---|---|---|---|
| 1 | Oct 17, 2025 | Blackrock, Inc. | 13G/A | 11.5% | 5.33M | SEC |
| 2 | Feb 7, 2025 | Jack Y. Zhang | 13G/A | 24.8% | 12.52M | SEC |
| 3 | Mar 6, 2024 | Federated Hermes, Inc. | 13G/A | 4.5% | 2.17M | SEC |
| 4 | Feb 13, 2024 | Vanguard Group Inc | 13G/A | 5.9% | 2.81M | SEC |
| 5 | Feb 9, 2024 | Zhang Jack Y. | 13G/A | 26.2% | 13.44M | SEC |
| 6 | Jan 23, 2024 | Blackrock Inc. | 13G/A | 12.6% | 6.04M | SEC |
| 7 | Jan 17, 2024 | Federated Hermes, Inc. | 13G/A | 6.8% | 3.27M | SEC |
| 8 | Feb 9, 2023 | Vanguard Group Inc | 13G/A | 5.4% | 2.62M | SEC |
| 9 | Feb 1, 2023 | Federated Hermes, Inc. | 13G/A | 6.8% | 3.28M | SEC |
| 10 | Jan 27, 2023 | Zhang Jack Y. | 13G/A | 25.5% | 13.11M | SEC |
15 more beneficial-ownership filings on Premium
See the full Schedule 13D/13G history for Amphastar Pharmaceuticals In.
Unlock full historyTop Institutional Holders (13F)
Largest reported positions · latest quarter
| # | Fund | Shares | Value |
|---|---|---|---|
| 1 | Blackrock, Inc. | 5.42M | $106.20M |
| 2 | Dimensional Fund Advisors LP | 2.03M | $39.73M |
| 3 | State Street Corp | 1.61M | $31.49M |
| 4 | Td Asset Management Inc | 1.54M | $30.19M |
| 5 | Fuller & Thaler Asset Management, Inc. | 1.40M | $27.33M |
| 6 | Marshall Wace, LLP | 1.03M | $20.09M |
| 7 | American Century Companies Inc | 1.02M | $19.93M |
| 8 | Geode Capital Management, LLC | 976.6K | $19.14M |
| 9 | Boston Trust Walden Corp | 944.8K | $18.51M |
| 10 | Epoch Investment Partners, Inc. | 898.9K | $17.61M |