Amphastar Pharmaceuticals
AMPH · NASDAQ
$25.94−$0.20 (−0.77%)TodayMarket closed ·
Prev close $26.14
Who owns AMPH
Largest institutional holders, from their latest 13F filings
The 10 largest institutions hold 58.6% of AMPH’s shares.
- Applied Physics & Chemistry Laboratories, Inc.15.5%
- BlackRock Institutional Trust Company, N.A.10.8%
- Zhang (Jack Yongfeng)7.4%
- Luo (Mary Z)5.3%
- Next 6 largest institutions19.6%
- All other shareholders41.4%
| Holder | Shares | % of shares |
|---|---|---|
| Applied Physics & Chemistry Laboratories, Inc. | 6.83M | 15.49% |
| BlackRock Institutional Trust Company, N.A. | 4.76M | 10.79% |
| Zhang (Jack Yongfeng) | 3.28M | 7.44% |
| Luo (Mary Z) | 2.32M | 5.25% |
| Dimensional Fund Advisors, L.P. | 2.31M | 5.23% |
| State Street Investment Management (US) | 1.64M | 3.72% |
| Vanguard Capital Management, LLC | 1.48M | 3.36% |
| American Century Investment Management, Inc. | 1.18M | 2.67% |
| Marshall Wace LLP | 1.07M | 2.42% |
| Geode Capital Management, L.L.C. | 969.84K | 2.20% |
Largest mutual fund holders
| Holder | Shares | % of shares |
|---|---|---|
| iShares Core S&P Small-Cap ETF | 2.07M | 4.68% |
| Fuller & Thaler Behavioral Small-Cap Equity Fund | 1.43M | 3.24% |
| Avantis US Small Cap Value ETF | 1.14M | 2.59% |
| Vanguard Total Stock Market Index Fund | 1.06M | 2.39% |
| iShares Russell 2000 ETF | 844.05K | 1.91% |
Insider trades
Form 4 filings by officers, directors and large holders
Over the last 6 months, insiders sold $763.92K (5 trades) of AMPH on the open market, with no buys.
| Insider | Type | Shares | Value |
|---|---|---|---|
| PETERS WILLIAM J | Sale | 4.14K | $103.47K |
| Zhou Rong | Option exercise | 10.00K | — |
| Zhou Rong | Sale | 10.00K | $239.40K |
| Zhou Rong | Option exercise | 10.00K | $133.50K |
| Zhou Rong | Sale | 3.19K | $75.31K |
| PRINS RICHARD K | Sale | 7.97K | $161.85K |
| PETERS WILLIAM J | Option exercise | 5.05K | — |
| PETERS WILLIAM J | Sale | 8.18K | $183.89K |
| PETERS WILLIAM J | Option exercise | 5.05K | $100.00K |
| Pierce Anthony T | Award | 16.65K | — |
Short interest
Settled Sep 30, 2026
- Shares short
- 4.41M
- Days to cover
- 7.10
- % of shares outstanding
- 9.99%
- Average daily volume
- 620.83K
- Change since last report
- −11.8%
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