Amphastar Pharmaceuticals's three largest insider shareholders as of April 22, 2026 are Jack Y. Zhang (Ceo Chief Scientific Officer, 4.24Mn shares), Mary Z. Luo (Coo,Chief Scientist Chairman, 1.10Mn shares), William J Peters (Cfo, Evp Treasurer, 175.06K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Jack Y. Zhang | Ceo Chief Scientific Officer | 2,990,052 | 1,245,125 | 17 Mar, 2026 |
| Mary Z. Luo | Coo,Chief Scientist Chairman | 1,104,416 | 0 | 11 Jan, 2024 |
| William J Peters | Cfo, Evp Treasurer | 175,063 | 0 | 17 Mar, 2026 |
| Rong Zhou | Senior Evp, Production Center | 174,994 | 0 | 11 Mar, 2026 |
| Rong Zhou | Senior Evp, Production Center | 171,554 | 0 | 17 Mar, 2026 |
| Howard Lee | - | 151,976 | 0 | 04 Jun, 2025 |
| Yakob Liawatidewi | Evp Corp Admin Center | 121,892 | 0 | 17 Mar, 2026 |
| Floyd F. Petersen | - | 71,368 | 0 | 15 Dec, 2025 |
| Richard K Prins | - | 35,183 | 0 | 25 Nov, 2025 |
| Michael A Zasloff | - | 29,524 | 0 | 04 Jun, 2025 |
| Diane G. Gerst | Evp, Qa Regulatory Affairs | 23,756 | 0 | 04 Jun, 2025 |
| Gayle Deflin | - | 10,914 | 0 | 04 Jun, 2025 |
| David Russell Gaugh | - | 6,304 | 0 | 22 Jul, 2025 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 15 Mar, 2026 | Yakob Liawatidewi | Common Stock | D | 1,033 | $18.18 | 121,892 | D | F |
| 15 Mar, 2026 | Rong Zhou | Common Stock | D | 1,225 | $18.18 | 171,554 | D | F |
| 15 Mar, 2026 | William J Peters | Common Stock | D | 1,973 | $18.18 | 175,063 | D | F |
| 15 Mar, 2026 | Jack Y. Zhang | Common Stock | D | 9,784 | $18.18 | 2,990,052 | D | F |
| 15 Mar, 2026 | Jack Y. Zhang | Common Stock | D | 2,908 | $18.18 | 1,245,125 | I | F |
| 09 Mar, 2026 | Yakob Liawatidewi | Common Stock | A | 35,450 | $0.00 | 124,795 | D | A |
| 09 Mar, 2026 | William J Peters | Common Stock | A | 58,693 | $0.00 | 180,333 | D | A |
| 09 Mar, 2026 | Rong Zhou | Common Srock | A | 39,432 | $0.00 | 174,994 | D | A |
| 09 Mar, 2026 | Jack Y. Zhang | Common Stock | A | 180,504 | $0.00 | 3,014,621 | D | A |
| 10 Mar, 2026 | Yakob Liawatidewi | Common Stock | D | 1,870 | $18.91 | 122,925 | D | F |
| 10 Mar, 2026 | Jack Y. Zhang | Common Stock | D | 14,785 | $18.91 | 2,999,836 | D | F |
| 10 Mar, 2026 | William J Peters | Common Stock | D | 3,297 | $18.91 | 177,036 | D | F |
| 10 Mar, 2026 | Rong Zhou | Common Stock | D | 2,215 | $18.91 | 172,779 | D | F |
| 09 Mar, 2026 | William J Peters | Employee Stock Option (right to buy) | A | 121,071 | $0.00 | 121,071 | D | A |
| 09 Mar, 2026 | Jack Y. Zhang | Common Stock | A | 72,462 | $0.00 | 1,252,428 | I | A |
| 10 Mar, 2026 | Jack Y. Zhang | Common Stock | D | 4,395 | $18.91 | 1,248,033 | I | F |
| 09 Mar, 2026 | Yakob Liawatidewi | Employee Stock Option (right to buy) | A | 73,126 | $0.00 | 73,126 | D | A |
| 09 Mar, 2026 | Rong Zhou | Employee Stock Option (right to buy) | A | 81,341 | $0.00 | 81,341 | D | A |
| 09 Mar, 2026 | Jack Y. Zhang | Employee Stock Option (right to buy) | A | 372,338 | $0.00 | 372,338 | D | A |
| 09 Mar, 2026 | Jack Y. Zhang | Employee Stock Option (right to buy) | A | 149,472 | $0.00 | 149,472 | I | A |