AMPH Insider Trading
Amphastar Pharmaceuticals Inc. | Pharmaceutical Preparations
Comprehensive Trading Performance Summary
The investment history of corporate insiders at Amphastar Pharmaceuticals Inc. provides a unique lens into the internal conviction of the company's leadership. By analyzing SEC Form 4 filings, investors can track how directors and officers are allocating their own capital. High-conviction buying often signals that management believes the current market price significantly undervalues future growth prospects, while strategic selling might occur for personal liquidity or portfolio diversification. Monitoring these shifts in ownership is essential for understanding the alignment between management and shareholders in the Pharmaceutical Preparations sector.
Transactions on Chart
Open Full Chart| Filing Date | Trade Date | Reporting Person | Relationship | Type | Price | Qty | Total, $ | Owned After | Change, % |
|---|---|---|---|---|---|---|---|---|---|
| 2025-12-19 01:23 | 2025-12-17 | Zhou Rong | Officer - SENIOR EVP, PRODUCTION CENTER | OPT+S | $26.20 | 9,787 | $256,379 | 138,043 | 0.0% |
| 2025-12-16 01:17 | 2025-12-11 | Petersen Floyd F. | Director | SELL | $25.82 | 4,163 | $107,508 | 71,368 | -5.5% |
| 2025-11-26 03:38 | 2025-11-25 | PRINS RICHARD K | Director | OPT+S | $27.10 | 4,179 | $113,253 | 35,183 | 0.0% |
| 2025-11-18 00:16 | 2025-11-13 | Petersen Floyd F. | Director | OPT+S | $26.49 | 16,679 | $441,837 | 75,531 | 0.0% |
| 2025-11-06 00:20 | 2025-11-03 | Petersen Floyd F. | Director | SELL | $25.27 | 500 | $12,633 | 75,531 | -0.7% |
| 2025-10-03 00:04 | 2025-10-01 | Petersen Floyd F. | Director | SELL | $27.20 | 500 | $13,602 | 76,031 | -0.7% |
| 2025-09-03 23:20 | 2025-09-02 | Petersen Floyd F. | Director | SELL | $30.98 | 500 | $15,492 | 76,531 | -0.6% |
| 2025-08-05 02:17 | 2025-08-01 | Petersen Floyd F. | Director | SELL | $20.83 | 500 | $10,416 | 77,031 | -0.6% |
| 2025-07-04 00:30 | 2025-07-02 | Petersen Floyd F. | Director | SELL | $23.47 | 500 | $11,734 | 77,531 | -0.6% |
| 2025-06-05 01:39 | 2025-06-02 | Petersen Floyd F. | Director | SELL | $25.67 | 500 | $12,835 | 72,909 | -0.7% |
| 2025-05-03 03:27 | 2025-05-01 | Petersen Floyd F. | Director | SELL | $24.08 | 500 | $12,041 | 73,409 | -0.7% |
| 2025-04-03 01:45 | 2025-04-01 | Petersen Floyd F. | Director | SELL | $28.38 | 500 | $14,190 | 73,909 | -0.7% |
| 2025-03-08 00:01 | 2025-03-06 | Petersen Floyd F. | Director | SELL | $27.99 | 1,000 | $27,986 | 74,409 | -1.3% |
| 2025-03-07 01:00 | 2025-03-04 | PETERS WILLIAM J | Director, Officer - CFO, EVP & TREASURER | OPT+S | $27.54 | 4,231 | $116,515 | 97,363 | 0.0% |
| 2024-12-17 01:22 | 2024-12-12 | Zhou Rong | Officer - SENIOR EVP, PRODUCTION CENTER | OPT+S | $44.85 | 15,000 | $672,815 | 118,469 | 0.0% |
| 2024-12-12 04:28 | 2024-12-09 | PRINS RICHARD K | Director | OPT+S | $43.77 | 10,000 | $437,702 | 30,471 | 0.0% |
| 2024-11-14 04:26 | 2024-11-12 | Zhou Rong | Officer - SENIOR EVP, PRODUCTION CENTER | OPT+S | $48.88 | 6,893 | $336,930 | 118,388 | 0.0% |
| 2024-11-14 02:55 | 2024-11-12 | PRINS RICHARD K | Director | OPT+S | $48.80 | 5,000 | $243,986 | 31,471 | 0.0% |
| 2024-11-09 03:02 | 2024-11-06 | Liawatidewi Yakob | Director, Officer - EVP CORP ADMIN CENTER | OPT+S | $52.05 | 5,214 | $271,389 | 74,938 | 0.0% |
| 2024-11-09 01:24 | 2024-11-06 | PETERS WILLIAM J | Director, Officer - CFO, EVP & TREASURER | OPT+S | $52.05 | 7,426 | $386,523 | 94,103 | 0.0% |
| 2024-09-17 23:11 | 2024-09-13 | Zhou Rong | Officer - SENIOR EVP, PRODUCTION CENTER | OPT+S | $48.26 | 3,000 | $144,785 | 118,388 | 0.0% |
| 2024-09-07 02:48 | 2024-09-05 | Petersen Floyd F. | Director | SELL | $46.47 | 3,000 | $139,417 | 75,409 | -3.8% |
| 2024-08-28 04:33 | 2024-08-26 | Zhou Rong | Officer - SENIOR EVP, PRODUCTION CENTER | OPT+S | $48.35 | 4,000 | $193,400 | 118,388 | 0.0% |
| 2024-08-14 00:58 | 2024-08-12 | PRINS RICHARD K | Director | OPT+S | $43.07 | 17,101 | $736,550 | 33,971 | 0.0% |
| 2024-08-02 23:32 | 2024-07-31 | PETERS WILLIAM J | Director, Officer - CFO, EVP & TREASURER | OPT+S | $44.23 | 10,282 | $454,773 | 94,103 | 0.0% |
| 2024-06-28 23:26 | 2024-06-27 | PETERS WILLIAM J | Director, Officer - CFO, EVP & TREASURER | SELL | $40.93 | 3,596 | $147,169 | 94,103 | -3.7% |
| 2024-06-12 01:32 | 2024-06-10 | Petersen Floyd F. | Director | SELL | $41.40 | 3,000 | $124,200 | 78,409 | -3.7% |
| 2024-06-06 01:54 | 2024-06-03 | Petersen Floyd F. | Director | SELL | $42.65 | 500 | $21,326 | 78,333 | -0.6% |
| 2024-05-02 23:56 | 2024-05-01 | Petersen Floyd F. | Director | SELL | $41.67 | 500 | $20,837 | 78,833 | -0.6% |
| 2024-04-03 04:31 | 2024-04-01 | Petersen Floyd F. | Director | SELL | $43.43 | 500 | $21,714 | 79,333 | -0.6% |
| 2024-03-09 00:52 | 2024-03-06 | PETERS WILLIAM J | Director, Officer - CFO, EVP & TREASURER | OPT+S | $46.48 | 18,136 | $842,883 | 111,490 | 0.0% |
| 2024-03-07 01:57 | 2024-03-05 | ZASLOFF MICHAEL A | Director | SELL | $47.18 | 12,500 | $589,724 | 21,326 | -37.0% |
| 2024-03-05 04:35 | 2024-03-01 | Petersen Floyd F. | Director | SELL | $45.69 | 500 | $22,847 | 79,833 | -0.6% |
| 2024-02-03 03:37 | 2024-02-01 | Petersen Floyd F. | Director | SELL | $53.10 | 500 | $26,548 | 80,333 | -0.6% |
| 2024-01-12 00:37 | 2024-01-10 | Luo Mary Z. | Director, Officer, 10% owner - COO,Chief Scientist & Chairman | SELL | $54.59 | 131,386 | $7,171,771 | 1,104,416 | -10.6% |
| 2024-01-11 02:27 | 2024-01-08 | Luo Mary Z. | Director, Officer, 10% owner - COO,Chief Scientist & Chairman | SELL | $58.23 | 219,800 | $12,798,712 | 1,235,802 | -15.1% |
| 2024-01-04 03:25 | 2024-01-02 | Petersen Floyd F. | Director | SELL | $61.37 | 500 | $30,683 | 80,833 | -0.6% |
| 2023-12-06 02:25 | 2023-12-01 | Zhou Rong | Officer - Senior EVP, Production Center | OPT+S | $59.03 | 7,830 | $462,196 | 112,420 | 0.0% |
| 2023-12-05 04:49 | 2023-12-01 | Petersen Floyd F. | Director | SELL | $57.90 | 500 | $28,952 | 81,333 | -0.6% |
| 2023-11-21 01:23 | 2023-11-17 | PRINS RICHARD K | Director | SELL | $55.86 | 4,000 | $223,446 | 31,895 | -11.1% |
| 2023-11-17 00:05 | 2023-11-14 | PETERS WILLIAM J | Director, Officer - CFO, EVP & Treasurer | OPT+S | $55.67 | 59,250 | $3,298,477 | 101,360 | 0.0% |
| 2023-11-16 00:30 | 2023-11-14 | Deflin Gayle | Director | SELL | $55.45 | 4,163 | $230,838 | 2,716 | -60.5% |
| 2023-11-16 00:31 | 2023-11-13 | PRINS RICHARD K | Director | SELL | $52.50 | 5,000 | $262,500 | 35,895 | -12.2% |
| 2023-11-03 03:37 | 2023-11-01 | Petersen Floyd F. | Director | SELL | $45.30 | 500 | $22,651 | 81,833 | -0.6% |
| 2023-10-04 01:38 | 2023-10-02 | Petersen Floyd F. | Director | SELL | $45.78 | 500 | $22,890 | 82,333 | -0.6% |
| 2023-09-08 23:08 | 2023-09-06 | PETERS WILLIAM J | Director, Officer - CFO, EVP & Treasurer | OPT+S | $51.75 | 60,743 | $3,143,195 | 101,360 | 0.0% |
| 2023-08-30 01:54 | 2023-08-28 | Liawatidewi Yakob | Director, Officer - EVP Corp Admin Center | OPT+S | $53.13 | 28,816 | $1,530,994 | 69,669 | 0.0% |
| 2023-08-21 23:05 | 2023-08-18 | PRINS RICHARD K | Director | SELL | $52.50 | 2,000 | $105,006 | 40,895 | -4.7% |
| 2023-08-17 03:22 | 2023-08-15 | PRINS RICHARD K | Director | SELL | $57.39 | 4,163 | $238,911 | 42,895 | -8.8% |
| 2023-08-17 03:23 | 2023-08-15 | ZASLOFF MICHAEL A | Director | SELL | $57.22 | 12,759 | $730,025 | 33,826 | -27.4% |
How to Interpret $AMPH Trades
Not every insider transaction in Amphastar Pharmaceuticals Inc. is a signal for immediate action. Professional investors look for "cluster buying"—when multiple executives simultaneously purchase $AMPH shares on the open market. It is crucial to distinguish between scheduled sales (under Rule 10b5-1) and voluntary increases in ownership, which demonstrate management’s true conviction that the stock is undervalued.
Data Source & Accuracy for AMPH
Insider activity data for Amphastar Pharmaceuticals Inc. is streamed in real-time directly from the SEC EDGAR system. We analyze raw Form 4 filings, filtering out technical adjustments and complex derivative transactions. This provides a transparent view of how ownership structure is evolving in $AMPH, allowing you to follow the capital of those with the most intimate knowledge of the company.
UNDERSTANDING THE DATA
FILING DATE: The date and time when the transaction was reported to the SEC. This is when the public first receives the information.
TRADE DATE: The actual day the insider executed the purchase or sale in the market.
INDUSTRY: The specific market sector the company operates in. Useful for identifying broader institutional capital flows across sectors.
OWNED AFTER: The total number of shares held by the insider following the transaction. This highlights the insider's remaining conviction in the company.
CHANGE %: The percentage increase or decrease of the insider's total position. Large percentage changes often carry more weight than the dollar amount alone.
TRADE TYPES DEFINITIONS
BUY: An open market purchase. Typically indicates an insider's belief that the stock is undervalued or poised for growth.
SELL: An open market sale. While often used for diversification or liquidity, large or unexpected sales can be a warning signal.
OPT+S (OPTION EXERCISE & SALE): This occurs when an insider exercises their stock options and sells them immediately. Often part of a structured compensation plan.