Zhang Jack Y. (CIK 1611157) reported 25 SEC Form 4 insider transactions across 1 companies over the past 18 months (most recent 2026-03-17). Recent activity: Sell AMPH (9,784 shares), Sell AMPH (2,908 shares), Buy AMPH (180,504 shares), Sell AMPH (14,785 shares), Buy AMPH (72,462 shares). Source: SEC Form 4.
| Date | Company | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-17 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 9,784 | $177,873 |
| 2026-03-17 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 2,908 | $52,867 |
| 2026-03-11 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 180,504 | $0 |
| 2026-03-11 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 14,785 | $279,584 |
| 2026-03-11 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 72,462 | $0 |
| 2026-03-11 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 4,395 | $83,109 |
| 2026-03-10 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 7,773 | $150,330 |
| 2026-03-10 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 3,077 | $59,509 |
| 2026-03-06 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 5,769 | $115,149 |
| 2026-03-06 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 2,432 | $48,543 |
| 2025-06-16 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 200,000 | $2.6M |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 226,285 | $6.0M |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 290,477 | $4.3M |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 9,765 | $260,335 |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 16,150 | $447,194 |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 211,213 | $3.1M |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 162,657 | $4.3M |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 4,115 | $109,706 |
| 2025-03-18 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 7,223 | $200,005 |
| 2025-03-12 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 116,226 | $0 |
| 2025-03-12 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Buy | 48,996 | $0 |
| 2025-03-10 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 9,645 | $273,146 |
| 2025-03-10 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 3,069 | $86,914 |
| 2025-03-06 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 5,753 | $158,898 |
| 2025-03-06 | Amphastar Pharmaceuticals, Inc. (AMPH) | CEO & CHIEF SCIENTIFIC OFFICER | Sell | 2,426 | $67,006 |
Source: SEC Form 4 filings · as of 2026-03-17