Amphastar Pharmaceuticals, Inc. (AMPH) has 16 known insider and institutional holders on record. The largest holder is Applied Physics & Chemistry Laboratories, Inc. with 7,394,837 shares. Other notable holders include Zhang Jack Y. and Luo Mary Z..
Over the last 12 months, insiders have made 42 transactions in AMPH stock — 11 buys (valued at $9.61M) and 8 sells (valued at $183.43K). Insider buying has outpaced selling during this period, which may signal confidence in the company's prospects.
AMPH Insider Ownership
Top Holder
Applied Physics & Chemistry Laboratories, Inc.
7,394,837 shares
Buys (12 mo)
11
$9.61M value
Sells (12 mo)
8
$183.43K value
12-Month Transaction Activity
Top Insider Holders
| # |
Name |
Role |
Shares Owned |
Last Filed |
Relative Size |
| 1 |
Applied Physics & Chemistry Laboratories, Inc. |
10 Percent Owner |
7,394,837 |
2018-12-13 |
|
| 2 |
Zhang Jack Y. |
10 Percent Owner, Officer: CEO & Chief Scientific Officer |
1,245,125 |
2026-03-17 |
|
| 3 |
Luo Mary Z. |
10 Percent Owner, Officer: COO,chief Scientist & Chairman |
1,104,416 |
2024-01-11 |
|
| 4 |
Peters William J |
CFO, EVP & Treasurer |
175,063 |
2026-03-17 |
|
| 5 |
Zhou Rong |
Senior EVP, Production Center |
171,554 |
2026-03-17 |
|
| 6 |
Shandell Jason B. |
President and General Counsel |
124,109 |
2020-03-18 |
|
| 7 |
Liawatidewi Yakob |
EVP Corp Admin Center |
121,892 |
2026-03-17 |
|
| 8 |
Petersen Floyd F. |
Director |
73,794 |
2025-12-15 |
|
| 9 |
Koo Richard |
Director |
17,182 |
2021-06-08 |
|
| 10 |
Maris David |
Director |
17,182 |
2021-06-08 |
|
| 11 |
Lee Howard |
Director |
11,402 |
2025-06-04 |
|
| 12 |
Zasloff Michael A |
Director |
11,402 |
2025-06-04 |
|
| 13 |
Gerst Diane G. |
Director |
11,402 |
2025-06-04 |
|
| 14 |
Prins Richard K |
Director |
11,402 |
2025-06-04 |
|
| 15 |
Deflin Gayle |
Director |
10,914 |
2025-06-04 |
|
| 16 |
Gaugh David Russell |
Director |
6,304 |
2025-07-22 |
|
Recent Transactions (last 12 months)
| Date |
Name |
Role |
Type |
Shares |
Price |
Value |
| 2026-03-15 |
Liawatidewi Yakob |
EVP Corp Admin Center |
Tax Withholding of RSU |
1,033 |
$18.18 |
$18.78K |
| 2026-03-15 |
Zhou Rong |
Senior EVP, Production Center |
Tax Withholding of RSU |
1,225 |
$18.18 |
$22.27K |
| 2026-03-15 |
Zhang Jack Y. |
10 Percent Owner, Officer: CEO & Chief Scientific Officer |
Tax Withholding of RSU |
2,908 |
$18.18 |
$52.87K |
| 2026-03-15 |
Peters William J |
CFO, EVP & Treasurer |
Tax Withholding of RSU |
1,973 |
$18.18 |
$35.87K |
| 2026-03-10 |
Liawatidewi Yakob |
EVP Corp Admin Center |
Tax Withholding of RSU |
1,870 |
$18.91 |
$35.36K |
| 2026-03-09 |
Liawatidewi Yakob |
EVP Corp Admin Center |
RSU Award |
73,126 |
$19.21 |
$1.4M |
| 2026-03-10 |
Zhou Rong |
Senior EVP, Production Center |
Tax Withholding of RSU |
2,215 |
$18.91 |
$41.89K |
| 2026-03-09 |
Zhou Rong |
Senior EVP, Production Center |
RSU Award |
81,341 |
$19.21 |
$1.56M |
| 2026-03-10 |
Zhang Jack Y. |
10 Percent Owner, Officer: CEO & Chief Scientific Officer |
Tax Withholding of RSU |
4,395 |
$18.91 |
$83.11K |
| 2026-03-09 |
Zhang Jack Y. |
10 Percent Owner, Officer: CEO & Chief Scientific Officer |
RSU Award |
149,472 |
$19.21 |
$2.87M |
| 2026-03-10 |
Peters William J |
CFO, EVP & Treasurer |
Tax Withholding of RSU |
3,297 |
$18.91 |
$62.35K |
| 2026-03-09 |
Peters William J |
CFO, EVP & Treasurer |
RSU Award |
121,071 |
$19.21 |
$2.33M |
| 2026-03-06 |
Liawatidewi Yakob |
EVP Corp Admin Center |
Tax Withholding of RSU |
1,144 |
$19.34 |
$22.12K |
| 2026-03-06 |
Zhou Rong |
Senior EVP, Production Center |
Tax Withholding of RSU |
1,357 |
$19.34 |
$26.24K |
| 2026-03-06 |
Zhang Jack Y. |
10 Percent Owner, Officer: CEO & Chief Scientific Officer |
Tax Withholding of RSU |
3,077 |
$19.34 |
$59.51K |
| 2026-03-06 |
Peters William J |
CFO, EVP & Treasurer |
Tax Withholding of RSU |
2,146 |
$19.34 |
$41.5K |
| 2026-03-04 |
Liawatidewi Yakob |
EVP Corp Admin Center |
Tax Withholding of RSU |
965 |
$19.96 |
$19.26K |
| 2026-03-04 |
Zhou Rong |
Senior EVP, Production Center |
Tax Withholding of RSU |
1,124 |
$19.96 |
$22.44K |
| 2026-03-04 |
Zhang Jack Y. |
10 Percent Owner, Officer: CEO & Chief Scientific Officer |
Tax Withholding of RSU |
2,432 |
$19.96 |
$48.54K |
| 2026-03-04 |
Peters William J |
CFO, EVP & Treasurer |
Tax Withholding of RSU |
1,744 |
$19.96 |
$34.81K |
| 2025-12-17 |
Zhou Rong |
Senior EVP, Production Center |
Option Exercise (Sell) |
9,787 |
$11.33 |
$110.89K |
| 2025-12-12 |
Petersen Floyd F. |
Director |
Informative Sell |
2,426 |
$25.92 |
$62.89K |
| 2025-12-11 |
Petersen Floyd F. |
Director |
Informative Sell |
1,737 |
$25.69 |
$44.62K |
| 2025-11-25 |
Prins Richard K |
Director |
Option Exercise (Sell) |
4,179 |
$16.69 |
$69.75K |
| 2025-11-13 |
Petersen Floyd F. |
Director |
Option Exercise (Sell) |
16,679 |
$16.69 |
$278.37K |
