Richard K Prins sold $162k of AMPH
director at Amphastar Pharmaceuticals, Inc.. 7,973 shares at an average of $20.30, traded Aug 11, 2026, filed Aug 12, 2026.
Score components
- +15RoleDirector
- +11Trade size$162k at market
- +5Share of holdings soldSold 21% of holdings
- +8Cluster2 insiders selling within 14 days
What happened after comparable sells
Same side and tier, against the S&P 500, at 1, 3 and 6 months. Shown to Pro users; the whole table is on the backtest page.
Price around the trade, and since
From a quarter before the trade to today. The arrow is the trade, the circle the day the filing reached EDGAR, which is the first day anyone outside could act; the dotted line is the S&P 500 rebased to that day's close.
Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value; the dashed line is the close on the filing day, the dotted line SPY rebased to it.Charts by TradingView Lightweight Charts™
Rows in this filing
Every transaction in Form 4 0001047579-26-000005, as filed. Open on EDGAR
| Date | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|
| Aug 11, 2026 | SOpen-market sale Common Stock | -7,973 | $20.30 | $162k | 29,625 | Aug 12, 2026 |
Related signals
Other insiders at Amphastar Pharmaceuticals, Inc. and this insider’s other filings.
| Score | Company | Insider | Value | Holdings | Filed |
|---|---|---|---|---|---|
| 20Weak | Amphastar Pharmaceuticals, Inc. | William J Peters CFO, EVP & TREASURER | $103k 4,139 shares | -2% | |
| 21Weak | Amphastar Pharmaceuticals, Inc. | Rong Zhou SENIOR EVP, PRODUCTION CENTER | $239k 10,000 shares | -6% | |
| 23Weak | AMPHsell Amphastar Pharmaceuticals, Inc. | Rong Zhou SENIOR EVP, PRODUCTION CENTER | $75k 3,187 shares | -2% | |
| 7Weak | Amphastar Pharmaceuticals, Inc. | William J Peters CFO, EVP & TREASURER | $184k 8,180 shares | -5% | |
| 21Weak | Amphastar Pharmaceuticals, Inc. | Rong Zhou SENIOR EVP, PRODUCTION CENTER | $256k 9,787 shares | -7% | |
| 33Weak | Amphastar Pharmaceuticals, Inc. | Floyd F. Petersen director | $108k 4,163 shares | -6% | |
| 23Weak | Amphastar Pharmaceuticals, Inc. | Richard K Prins director | $113k 4,179 shares | -11% | |
| 30Weak | Amphastar Pharmaceuticals, Inc. | Floyd F. Petersen director | $442k 16,679 shares | -18% | |
| 0Weak | Amphastar Pharmaceuticals, Inc. | Floyd F. Petersen director | $13k 500 shares | -1% | |
| 0Weak | Amphastar Pharmaceuticals, Inc. | Floyd F. Petersen director | $14k 500 shares | -1% |
Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.