In the last 12 months, insiders at Amphastar Pharmaceuticals made open-market sales of $1.7 million (68.79K shares) and bought no shares on the open market.
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Jack Y. Zhang | Ceo Chief Scientific Officer | 2,990,052 | 1,245,125 | 4,235,177 | 66.7% | 17 Mar, 2026 |
| 2 | Mary Z. Luo | Coo,Chief Scientist Chairman | 1,104,416 | 0 | 1,104,416 | 17.4% | 11 Jan, 2024 |
| 3 | Rong Zhou | Senior Evp, Production Center | 344,197 | 0 | 344,197 | 5.4% | 17 Sep, 2026 |
| 4 | William J Peters | Cfo, Evp Treasurer | 168,707 | 0 | 168,707 | 2.7% | 23 Sep, 2026 |
| 5 | Howard Lee | Director | 159,350 | 0 | 159,350 | 2.5% | 03 Jun, 2026 |
| 6 | Yakob Liawatidewi | Evp Corp Admin Center | 121,892 | 0 | 121,892 | 1.9% | 17 Mar, 2026 |
| 7 | Floyd F. Petersen | Director | 71,368 | 0 | 71,368 | 1.1% | 15 Dec, 2025 |
| 8 | Michael A Zasloff | Director | 37,667 | 0 | 37,667 | 0.6% | 03 Jun, 2026 |
| 9 | Diane G. Gerst | Evp, Qa Regulatory Affairs | 31,899 | 0 | 31,899 | 0.5% | 03 Jun, 2026 |
| 10 | Richard K Prins | Director | 29,625 | 0 | 29,625 | 0.5% | 12 Aug, 2026 |
| 11 | Gayle Deflin | Director | 19,057 | 0 | 19,057 | 0.3% | 03 Jun, 2026 |
| 12 | David Russell Gaugh | Director | 14,447 | 0 | 14,447 | 0.2% | 03 Jun, 2026 |
| 13 | Anthony T Pierce | Director | 7,886 | 0 | 7,886 | 0.1% | 13 Jul, 2026 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 21 Sep, 2026 | William J Peters | Cfo, Evp Treasurer | Disposed S | 4,139 | $25.00 | $103.48K | 168,707 | Direct |
| 16 Sep, 2026 | Rong Zhou | Senior Evp, Production Center | Acquired M | 10,000 | $13.35 | $133.50K | 179,203 | Direct |
| 16 Sep, 2026 | Rong Zhou | Senior Evp, Production Center | Disposed S | 10,000 | $23.94 | $239.40K | 169,203 | Direct |
| 16 Sep, 2026 | Rong Zhou | Senior Evp, Production Center | Disposed M | 10,000 | $0.00 | $0 | 19,424 | Direct |
| 02 Sep, 2026 | Rong Zhou | Senior Evp, Production Center | Disposed S | 3,187 | $23.63 | $75.31K | 169,203 | Direct |
| 11 Aug, 2026 | Richard K Prins | Director | Disposed S | 7,973 | $20.30 | $161.85K | 29,625 | Direct |
| 07 Aug, 2026 | William J Peters | Cfo, Evp Treasurer | Acquired M | 5,053 | $19.79 | $100.00K | 181,026 | Direct |
| 07 Aug, 2026 | William J Peters | Cfo, Evp Treasurer | Disposed S | 8,180 | $22.48 | $183.89K | 172,846 | Direct |
| 07 Aug, 2026 | William J Peters | Cfo, Evp Treasurer | Disposed M | 5,053 | $0.00 | $0 | 0 | Direct |
| 09 Jul, 2026 | Anthony T Pierce | Director | Acquired A | 7,886 | $0.00 | $0 | 7,886 | Direct |
| 09 Jul, 2026 | Anthony T Pierce | Director | Acquired A | 16,646 | $0.00 | $0 | 16,646 | Direct |
| 01 Jun, 2026 | Gayle Deflin | Director | Acquired A | 8,143 | $0.00 | $0 | 19,057 | Direct |
| 01 Jun, 2026 | David Russell Gaugh | Director | Acquired A | 8,143 | $0.00 | $0 | 14,447 | Direct |
| 01 Jun, 2026 | Howard Lee | Director | Acquired A | 8,143 | $0.00 | $0 | 160,119 | Direct |
| 01 Jun, 2026 | Michael A Zasloff | Director | Acquired A | 8,143 | $0.00 | $0 | 37,667 | Direct |
| 01 Jun, 2026 | Diane G. Gerst | Director | Acquired A | 8,143 | $0.00 | $0 | 31,899 | Direct |
| 01 Jun, 2026 | Diane G. Gerst | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 01 Jun, 2026 | Michael A Zasloff | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 01 Jun, 2026 | Gayle Deflin | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 01 Jun, 2026 | David Russell Gaugh | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |