Amphastar Pharmaceuticals, Inc. (AMPH)
Who owns Amphastar Pharmaceuticals, Inc. (AMPH)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 74.5% of the shares are freely tradable; institutional investors hold 76.5%.
Ownership Structure
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 12.30 | 5,421,343 | -0.7 | 03/31/2026 |
| Vanguard Group Inc | 5.92 | 2,608,158 | -0.9 | 12/31/2025 |
| Dimensional Fund Advisors, Inc. | 4.60 | 2,027,947 | +12.7 | 03/31/2026 |
| State Street Corp | 3.65 | 1,607,515 | +4.9 | 03/31/2026 |
| Vanguard Capital Management, LLC | 3.50 | 1,543,655 | +0.0 | 03/31/2026 |
| TD Asset Management Inc | 3.50 | 1,541,044 | -21.5 | 03/31/2026 |
| Fuller & Thaler Asset Management Inc | 3.16 | 1,395,139 | -50.0 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| iShares Core S&P Small-Cap ETF | 4.86 | 2,145,094 | +0.0 | 05/29/2026 |
| FullerThaler Behavioral Sm-Cp Eq R6 | 3.24 | 1,428,937 | +6.9 | 04/30/2026 |
| FullerThaler Behavioral Small-Cap Equity | 3.03 | 1,336,827 | +3.6 | 12/31/2025 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 9. Jul 2026 | Pierce Anthony T | Director | Other | 7,886 | 0.00 | – |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character.
View all insider transactions →Data as of: July 31, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.