AMPH — Amphastar Pharmaceuticals, Inc.
Price · 2024-08-26 → 2026-08-21
499 daily closes shownAnonymous view is capped at two years of history. A free account extends it to five, and Pro opens the whole archive back to 2016-01-04.
Performance
Technicals
Others in Healthcare
Measured signals that fired on AMPH
| date | signal | measured base rate |
|---|---|---|
| 2026-08-17 | Fair value gap, bullish structure | -0.67% over 21 days · t = -6.43 · n = 111,973 statistically distinguishable from its control group |
| 2026-07-29 | Fair value gap, bullish structure | -0.67% over 21 days · t = -6.43 · n = 111,973 statistically distinguishable from its control group |
| 2026-07-09 | Fair value gap, bearish structure | -0.45% over 21 days · t = -3.29 · n = 108,591 statistically distinguishable from its control group |
| 2026-06-05 | Fair value gap, bullish structure | -0.67% over 21 days · t = -6.43 · n = 111,973 statistically distinguishable from its control group |
| 2026-05-18 | Equal lows taken out structure | -0.64% over 21 days · t = -4.75 · n = 55,661 statistically distinguishable from its control group |
| 2026-04-22 | Fair value gap, bearish structure | -0.45% over 21 days · t = -3.29 · n = 108,591 statistically distinguishable from its control group |
Excess return against a matched control group, on a point-in-time universe that includes delisted companies. Most families do not survive that. How the measurement works →
Insider transactions (Form 4)
| date | insider | what | shares | price | value |
|---|---|---|---|---|---|
| 2026-08-11 | PRINS RICHARD K Director | Open-market sale | 8.0K | 20.30 | 161.9K |
| 2026-08-07 | PETERS WILLIAM J CFO, EVP & TREASURER | Open-market sale 10b5-1 plan | 8.2K | 22.48 | 183.9K |
| 2026-08-07 | PETERS WILLIAM J CFO, EVP & TREASURER | Option exercise 10b5-1 plan | 5.1K | 19.79 | 100.0K |
| 2026-07-09 | Pierce Anthony T Director | Grant or award | 7.9K | 0.00 | 0 |
| 2026-06-02 | Lee Howard Director | Shares withheld for tax | 769 | 18.45 | 14.2K |
| 2026-06-01 | PRINS RICHARD K Director | Grant or award | 8.1K | 0.00 | 0 |
| 2026-06-01 | ZASLOFF MICHAEL A Director | Grant or award | 8.1K | 0.00 | 0 |
| 2026-06-01 | Gerst Diane G. Director | Grant or award | 8.1K | 0.00 | 0 |
| 2026-06-01 | Lee Howard Director | Grant or award | 8.1K | 0.00 | 0 |
| 2026-06-01 | Deflin Gayle Director | Grant or award | 8.1K | 0.00 | 0 |
Open-market purchases (code P) are the informative ones. Grants, option exercises and tax withholding are compensation mechanics, not decisions. How to read a Form 4 →
Largest institutional holders
| manager | value | shares |
|---|---|---|
| BlackRock, Inc. | 106.2M | 5.4M |
| DIMENSIONAL FUND ADVISORS LP | 39.7M | 2.0M |
| STATE STREET CORP | 31.5M | 1.6M |
| VANGUARD CAPITAL MANAGEMENT LLC | 30.2M | 1.5M |
| TD Asset Management Inc | 30.2M | 1.5M |
| FULLER & THALER ASSET MANAGEMENT, INC. | 27.3M | 1.4M |
| MARSHALL WACE, LLP | 20.1M | 1.0M |
| AMERICAN CENTURY COMPANIES INC | 19.9M | 1.0M |
| GEODE CAPITAL MANAGEMENT, LLC | 19.1M | 976.6K |
| Boston Trust Walden Corp | 18.5M | 944.8K |
13F positions as of 2026-03-31, filed up to 45 days after quarter end. Long-only US equity — shorts and derivatives never appear. What 13F does and does not show →
Latest SEC filings
| form | filed | period | |
|---|---|---|---|
| 144 | 2026-08-18 | — | on EDGAR ↗ |
| 4 | 2026-08-12 | 2026-08-11 | on EDGAR ↗ |
| 4 | 2026-08-11 | 2026-08-07 | on EDGAR ↗ |
| 144 | 2026-08-11 | — | on EDGAR ↗ |
| 144 | 2026-08-07 | — | on EDGAR ↗ |
| 10-Q | 2026-08-06 | 2026-06-30 | on EDGAR ↗ |
| 8-K | 2026-08-06 | 2026-08-06 | on EDGAR ↗ |
| SCHEDULE 13G | 2026-07-14 | — | on EDGAR ↗ |
Short selling
This is off-exchange short volume, not short interest: it is flow, not position, and 40–50% is normal because market makers short to fill your buy. Why that number misleads →
Recent headlines
- Amphastar Pharmaceuticals, Inc. (AMPH) filed form 144 · 2026-08-18 · SEC EDGAR
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