Amphastar Pharmaceuticals, Inc.
AMPHHealthcare|Drug Manufacturers - Specialty & Generic|US
$28.49
+0.83 (+3.00%)
DCF Value
$89.04
Tangible Book / Share
$4.09
Graham Number
$31.63
Cash / Share
$5.42
Ownership Breakdown
73.8%
Float
42.5M
Shares Outstanding
31.4M
Float Shares
Major Holders (5)
Combined: 80.5%
Holders of 5%+ from their latest Schedule 13D/13G filing in the last two years. Percentages are as of each filing date.
| Holder | Type | % of Class | Shares | Filed | Filing |
|---|---|---|---|---|---|
| Jack Y. Zhang | Individual | 24.80% | 12,524,153 | Feb 7, 2025 | 13D/G |
| Mary Z. Luo | Individual | 24.80% | 12,524,153 | Feb 7, 2025 | 13D/G |
| Applied Physics & Chemistry Laboratories, Inc. | Corporation | 14.20% | 6,827,679 | Feb 7, 2025 | 13D/G |
| BlackRock, Inc. | Holding company | 11.50% | 5,333,463 | Oct 17, 2025 | 13D/G |
| Dimensional Fund Advisors LP | Investment adviser | 5.20% | 2,305,107 | Jul 14, 2026 | 13D/G |
Insider Trades (100)
Last 4 quarters: 1,403,522 acquired · 175,948 disposed
| Insider | Position | Date | Type | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Nov 4, 2026 | OPTION EX. | 16,000 | $13.03 | $208.5K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Nov 5, 2026 | OPTION EX. | 11,000 | $17.99 | $197.9K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Nov 4, 2026 | SELL | 16,000 | $28.03 | $448.5K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Nov 5, 2026 | SELL | 12,631 | $28.99 | $366.2K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Nov 5, 2026 | OPTION EX. | 11,000 | $17.99 | $197.9K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Nov 4, 2026 | OPTION EX. | 16,000 | $13.03 | $208.5K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Sep 21, 2026 | SELL | 4,139 | $25.00 | $103.5K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sep 16, 2026 | OPTION EX. | 10,000 | $13.35 | $133.5K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sep 16, 2026 | SELL | 10,000 | $23.94 | $239.4K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sep 16, 2026 | OPTION EX. | 10,000 | $13.35 | $133.5K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sep 2, 2026 | SELL | 3,187 | $23.63 | $75.3K | Form 4 |
| PRINS RICHARD K | director | Aug 11, 2026 | SELL | 7,973 | $20.30 | $161.9K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Aug 7, 2026 | OPTION EX. | 5,053 | $19.79 | $100.0K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Aug 7, 2026 | SELL | 8,180 | $22.48 | $183.9K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Aug 7, 2026 | OPTION EX. | 5,053 | $19.79 | $100.0K | Form 4 |
| Pierce Anthony T | director | Jul 9, 2026 | AWARD | 16,646 | $19.02 | $316.6K | Form 4 |
| Pierce Anthony T | director | Jul 9, 2026 | AWARD | 7,886 | — | — | Form 4 |
| Pierce Anthony T | Jul 9, 2026 | OTHER | 0 | — | — | Form 4 | |
| PRINS RICHARD K | director | Jun 1, 2026 | AWARD | 8,143 | — | — | Form 4 |
| PRINS RICHARD K | director | Aug 19, 2024 | GIFT | 1,500 | — | — | Form 4 |
| PRINS RICHARD K | director | Jun 1, 2026 | AWARD | 17,365 | $18.42 | $319.9K | Form 4 |
| Lee Howard | director | Jun 1, 2026 | AWARD | 8,143 | — | — | Form 4 |
| Lee Howard | director | Jun 2, 2026 | TAX W/H | 769 | $18.45 | $14.2K | Form 4 |
| Lee Howard | director | Jun 1, 2026 | AWARD | 17,365 | $18.42 | $319.9K | Form 4 |
| ZASLOFF MICHAEL A | director | Jun 1, 2026 | AWARD | 8,143 | — | — | Form 4 |
| ZASLOFF MICHAEL A | director | Jun 1, 2026 | AWARD | 17,365 | $18.42 | $319.9K | Form 4 |
| Gerst Diane G. | director | Jun 1, 2026 | AWARD | 8,143 | — | — | Form 4 |
| Gerst Diane G. | director | Jun 1, 2026 | AWARD | 17,365 | $18.42 | $319.9K | Form 4 |
| Gaugh David Russell | director | Jun 1, 2026 | AWARD | 17,365 | $18.42 | $319.9K | Form 4 |
| Gaugh David Russell | director | Jun 1, 2026 | AWARD | 8,143 | — | — | Form 4 |
| Deflin Gayle | director | Jun 1, 2026 | AWARD | 8,143 | — | — | Form 4 |
| Deflin Gayle | director | Jun 1, 2026 | AWARD | 17,365 | $18.42 | $319.9K | Form 4 |
| Liawatidewi Yakob | director, officer: EVP CORP ADMIN CENTER | Mar 15, 2026 | TAX W/H | 1,033 | $18.18 | $18.8K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Mar 15, 2026 | TAX W/H | 1,225 | $18.18 | $22.3K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Mar 15, 2026 | TAX W/H | 1,973 | $18.18 | $35.9K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 15, 2026 | TAX W/H | 9,784 | $18.18 | $177.9K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 15, 2026 | TAX W/H | 2,908 | $18.18 | $52.9K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Mar 9, 2026 | AWARD | 58,693 | — | — | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Mar 10, 2026 | TAX W/H | 3,297 | $18.91 | $62.3K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Mar 9, 2026 | AWARD | 121,071 | $19.21 | $2.3M | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Mar 9, 2026 | AWARD | 39,432 | — | — | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Mar 10, 2026 | TAX W/H | 2,215 | $18.91 | $41.9K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Mar 9, 2026 | AWARD | 81,341 | $19.21 | $1.6M | Form 4 |
| Liawatidewi Yakob | director, officer: EVP CORP ADMIN CENTER | Mar 9, 2026 | AWARD | 35,450 | — | — | Form 4 |
| Liawatidewi Yakob | director, officer: EVP CORP ADMIN CENTER | Mar 10, 2026 | TAX W/H | 1,870 | $18.91 | $35.4K | Form 4 |
| Liawatidewi Yakob | director, officer: EVP CORP ADMIN CENTER | Mar 9, 2026 | AWARD | 73,126 | $19.21 | $1.4M | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 9, 2026 | AWARD | 180,504 | — | — | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 10, 2026 | TAX W/H | 14,785 | $18.91 | $279.6K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 9, 2026 | AWARD | 72,462 | — | — | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 10, 2026 | TAX W/H | 4,395 | $18.91 | $83.1K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 9, 2026 | AWARD | 372,338 | $19.21 | $7.2M | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 9, 2026 | AWARD | 149,472 | $19.21 | $2.9M | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Mar 6, 2026 | TAX W/H | 2,146 | $19.34 | $41.5K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Mar 6, 2026 | TAX W/H | 1,357 | $19.34 | $26.2K | Form 4 |
| Liawatidewi Yakob | director, officer: EVP CORP ADMIN CENTER | Mar 6, 2026 | TAX W/H | 1,144 | $19.34 | $22.1K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 6, 2026 | TAX W/H | 7,773 | $19.34 | $150.3K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 6, 2026 | TAX W/H | 3,077 | $19.34 | $59.5K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 4, 2026 | TAX W/H | 5,769 | $19.96 | $115.1K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Mar 4, 2026 | TAX W/H | 2,432 | $19.96 | $48.5K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Mar 4, 2026 | TAX W/H | 1,124 | $19.96 | $22.4K | Form 4 |
| Liawatidewi Yakob | director, officer: EVP CORP ADMIN CENTER | Mar 4, 2026 | TAX W/H | 965 | $19.96 | $19.3K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | Mar 4, 2026 | TAX W/H | 1,744 | $19.96 | $34.8K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Dec 17, 2025 | OPTION EX. | 9,787 | $11.33 | $110.9K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Dec 17, 2025 | SELL | 9,787 | $26.20 | $256.4K | Form 4 |
| Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Dec 17, 2025 | OPTION EX. | 9,787 | $11.33 | $110.9K | Form 4 |
| Petersen Floyd F. | director | Dec 11, 2025 | SELL | 1,737 | $25.69 | $44.6K | Form 4 |
| Petersen Floyd F. | director | Dec 12, 2025 | SELL | 2,426 | $25.92 | $62.9K | Form 4 |
| PRINS RICHARD K | director | Nov 25, 2025 | OPTION EX. | 4,179 | $16.69 | $69.7K | Form 4 |
| PRINS RICHARD K | director | Nov 25, 2025 | SELL | 4,179 | $27.10 | $113.3K | Form 4 |
| PRINS RICHARD K | director | Nov 25, 2025 | OPTION EX. | 4,179 | $16.69 | $69.7K | Form 4 |
| Petersen Floyd F. | director | Nov 13, 2025 | OPTION EX. | 16,679 | $16.69 | $278.4K | Form 4 |
| Petersen Floyd F. | director | Nov 13, 2025 | SELL | 16,679 | $26.49 | $441.8K | Form 4 |
| Petersen Floyd F. | director | Nov 13, 2025 | OPTION EX. | 16,679 | $16.69 | $278.4K | Form 4 |
| Petersen Floyd F. | director | Nov 3, 2025 | SELL | 500 | $25.27 | $12.6K | Form 4 |
| Petersen Floyd F. | director | Oct 1, 2025 | SELL | 500 | $27.20 | $13.6K | Form 4 |
| Petersen Floyd F. | director | Sep 2, 2025 | SELL | 500 | $30.98 | $15.5K | Form 4 |
| Petersen Floyd F. | director | Aug 1, 2025 | SELL | 500 | $20.83 | $10.4K | Form 4 |
| Gaugh David Russell | director | Jul 18, 2025 | AWARD | 13,987 | $20.62 | $288.4K | Form 4 |
| Gaugh David Russell | director | Jul 18, 2025 | AWARD | 6,304 | — | — | Form 4 |
| Gaugh David Russell | Jul 18, 2025 | OTHER | 0 | — | — | Form 4 | |
| Petersen Floyd F. | director | Jul 2, 2025 | SELL | 500 | $23.47 | $11.7K | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Jun 13, 2025 | OPTION EX. | 200,000 | $13.03 | $2.6M | Form 4 |
| Zhang Jack Y. | director, 10 percent owner, officer: CEO & CHIEF SCIENTIFIC OFFICER | Jun 13, 2025 | OPTION EX. | 200,000 | $13.03 | $2.6M | Form 4 |
| Lee Howard | director | Jun 2, 2025 | AWARD | 5,122 | — | — | Form 4 |
| Lee Howard | director | Jun 3, 2025 | TAX W/H | 923 | $26.01 | $24.0K | Form 4 |
| Lee Howard | director | Jun 2, 2025 | AWARD | 11,402 | $25.38 | $289.4K | Form 4 |
| Deflin Gayle | director | Jun 2, 2025 | AWARD | 11,402 | $25.38 | $289.4K | Form 4 |
| Deflin Gayle | director | Jun 2, 2025 | AWARD | 5,122 | — | — | Form 4 |
| Gerst Diane G. | director | Jun 2, 2025 | AWARD | 5,122 | — | — | Form 4 |
| Gerst Diane G. | director | Jun 2, 2025 | AWARD | 11,402 | $25.38 | $289.4K | Form 4 |
| PRINS RICHARD K | director | Jun 2, 2025 | AWARD | 5,122 | — | — | Form 4 |
| PRINS RICHARD K | director | Jun 2, 2025 | AWARD | 11,402 | $25.38 | $289.4K | Form 4 |
| Petersen Floyd F. | director | Jun 2, 2025 | AWARD | 5,122 | — | — | Form 4 |
| Petersen Floyd F. | director | Jun 2, 2025 | SELL | 500 | $25.67 | $12.8K | Form 4 |
| Petersen Floyd F. | director | Jun 2, 2025 | AWARD | 11,402 | $25.38 | $289.4K | Form 4 |
| ZASLOFF MICHAEL A | director | Jun 2, 2025 | AWARD | 5,122 | — | — | Form 4 |
| ZASLOFF MICHAEL A | director | Jun 2, 2025 | AWARD | 11,402 | $25.38 | $289.4K | Form 4 |
| PETERS WILLIAM J | director, officer: CFO, EVP & TREASURER | May 19, 2025 | TAX W/H | 273 | $24.79 | $6.8K | Form 4 |
| Petersen Floyd F. | director | May 1, 2025 | SELL | 500 | $24.08 | $12.0K | Form 4 |
| Petersen Floyd F. | director | Apr 1, 2025 | SELL | 500 | $28.38 | $14.2K | Form 4 |