AMPH
Amphastar Pharmaceuticals, Inc.
Pharmaceutical PreparationsNasdaqLarge accelerated filer
Total Trades
153
Buys
0
Sells
100
Largest Trade
N/A
Insiders
10
Institutional Funds
193
Inst. Value
$1M+
Activist Filings
15
Insider Trades
| Insider | Title | Type | Value | Shares | Price | Date |
|---|---|---|---|---|---|---|
| Zhou Rong | SENIOR EVP | SELL | $100K–$500K | 10K | $26.20 | Dec 18, 2025 |
| Zhou Rong | SENIOR EVP | EXERCISE | $100K–$500K | 10K | $11.33 | Dec 18, 2025 |
| Petersen Floyd F. | Director | SELL | $100K–$500K | 4K | $25.82 | Dec 15, 2025 |
| PRINS RICHARD K | Director | EXERCISE | $50K–$100K | 4K | $16.69 | Nov 26, 2025 |
| PRINS RICHARD K | Director | SELL | $100K–$500K | 4K | $27.10 | Nov 26, 2025 |
| Petersen Floyd F. | Director | EXERCISE | $100K–$500K | 17K | $16.69 | Nov 17, 2025 |
| Petersen Floyd F. | Director | SELL | $100K–$500K | 17K | $26.49 | Nov 17, 2025 |
| Petersen Floyd F. | Director | SELL | $1K–$15K | 500 | $25.27 | Nov 5, 2025 |
| Petersen Floyd F. | Director | SELL | $1K–$15K | 500 | $27.20 | Oct 2, 2025 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $30.98 | Sep 3, 2025 |
| Petersen Floyd F. | Director | SELL | $1K–$15K | 500 | $23.47 | Jul 3, 2025 |
| Petersen Floyd F. | Director | SELL | $1K–$15K | 500 | $25.67 | Jun 4, 2025 |
| Petersen Floyd F. | Director | GRANT | N/A | 5K | — | Jun 4, 2025 |
| Petersen Floyd F. | Director | SELL | $1K–$15K | 500 | $24.08 | May 3, 2025 |
| Petersen Floyd F. | Director | SELL | $1K–$15K | 500 | $28.38 | Apr 2, 2025 |
| Zhou Rong | SENIOR EVP | EXERCISE | $100K–$500K | 7K | $14.95 | Nov 14, 2024 |
| Zhou Rong | SENIOR EVP | SELL | $100K–$500K | 7K | $48.88 | Nov 14, 2024 |
| PRINS RICHARD K | Director | SELL | $100K–$500K | 5K | $48.80 | Nov 13, 2024 |
| PRINS RICHARD K | Director | EXERCISE | $15K–$50K | 3K | $16.69 | Nov 13, 2024 |
| Liawatidewi Yakob | EVP CORP ADMIN CEN… | SELL | $100K–$500K | 5K | $52.05 | Nov 9, 2024 |
| Liawatidewi Yakob | EVP CORP ADMIN CEN… | EXERCISE | $50K–$100K | 5K | $13.03 | Nov 9, 2024 |
| PETERS WILLIAM J | CFO, EVP & TREASURER | SELL | $100K–$500K | 7K | $52.05 | Nov 8, 2024 |
| PETERS WILLIAM J | CFO, EVP & TREASURER | EXERCISE | $50K–$100K | 7K | $13.03 | Nov 8, 2024 |
| Zhou Rong | SENIOR EVP | EXERCISE | $50K–$100K | 4K | $14.95 | Aug 28, 2024 |
| Zhou Rong | SENIOR EVP | SELL | $100K–$500K | 4K | $48.35 | Aug 28, 2024 |
| PETERS WILLIAM J | CFO, EVP & TREASURER | EXERCISE | $100K–$500K | 10K | $20.23 | Aug 2, 2024 |
| PETERS WILLIAM J | CFO, EVP & TREASURER | SELL | $100K–$500K | 10K | $44.23 | Aug 2, 2024 |
| PETERS WILLIAM J | CFO, EVP & TREASURER | SELL | $100K–$500K | 4K | $40.93 | Jun 28, 2024 |
| Petersen Floyd F. | Director | SELL | $100K–$500K | 3K | $41.40 | Jun 11, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $42.65 | Jun 5, 2024 |
| Petersen Floyd F. | Director | GRANT | N/A | 3K | — | Jun 5, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $41.67 | May 2, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $43.43 | Apr 3, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $45.69 | Mar 5, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $53.10 | Feb 3, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $61.37 | Jan 4, 2024 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $57.90 | Dec 5, 2023 |
| PRINS RICHARD K | Director | SELL | $100K–$500K | 4K | $55.86 | Nov 20, 2023 |
| PETERS WILLIAM J | CFO, EVP & Treasurer | SELL | $1M+ | 59K | $55.67 | Nov 16, 2023 |
| PETERS WILLIAM J | CFO, EVP & Treasurer | EXERCISE | $500K+ | 59K | $15.61 | Nov 16, 2023 |
| PRINS RICHARD K | Director | SELL | $100K–$500K | 5K | $52.50 | Nov 15, 2023 |
| Deflin Gayle | Director | SELL | $100K–$500K | 4K | $55.45 | Nov 15, 2023 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $45.30 | Nov 3, 2023 |
| Petersen Floyd F. | Director | SELL | $15K–$50K | 500 | $45.78 | Oct 3, 2023 |
| PETERS WILLIAM J | CFO, EVP & Treasurer | SELL | $1M+ | 61K | $51.75 | Sep 8, 2023 |
| PETERS WILLIAM J | CFO, EVP & Treasurer | EXERCISE | $500K+ | 57K | $16.93 | Sep 8, 2023 |
| Liawatidewi Yakob | EVP Corp Admin Cen… | EXERCISE | $100K–$500K | 29K | $14.86 | Aug 29, 2023 |
| Liawatidewi Yakob | EVP Corp Admin Cen… | SELL | $1M+ | 29K | $53.13 | Aug 29, 2023 |
| PRINS RICHARD K | Director | SELL | $100K–$500K | 2K | $52.50 | Aug 21, 2023 |
| ZASLOFF MICHAEL A | Director | SELL | $500K+ | 13K | $57.22 | Aug 17, 2023 |
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Institutional Ownership
13F filings as of Dec 31, 2025 · 193 funds holding
| Fund | Shares | Value | Type |
|---|---|---|---|
| TD ASSET MANAGEMENT INC | 2.0M | $1M+ | SH |
| DIMENSIONAL FUND ADVISORS LP | 1.7M | $1M+ | SH |
| STATE STREET CORP | 1.5M | $1M+ | SH |
| FULLER & THALER ASSET MANAGEMENT, INC. | 1.4M | $1M+ | SH |
| FULLER & THALER ASSET MANAGEMENT, INC. | 1.4M | $1M+ | SH |
| Epoch Investment Partners, Inc. | 1.1M | $1M+ | SH |
| GEODE CAPITAL MANAGEMENT, LLC | 770K | $1M+ | SH |
| Boston Trust Walden Corp | 668K | $1M+ | SH |
| AMERICAN CENTURY COMPANIES INC | 665K | $1M+ | SH |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 559K | $1M+ | SH |
| RENAISSANCE TECHNOLOGIES LLC | 545K | $1M+ | SH |
| ROYCE & ASSOCIATES LP | 352K | $1M+ | SH |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 351K | $1M+ | SH |
| VICTORY CAPITAL MANAGEMENT INC | 305K | $1M+ | SH |
| Bridge City Capital, LLC | 235K | $1M+ | SH |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC | 231K | $1M+ | SH |
| MARSHALL WACE, LLP | 215K | $1M+ | SH |
| DENALI ADVISORS LLC | 212K | $1M+ | SH |
| Pacer Advisors, Inc. | 178K | $1M+ | SH |
| Empowered Funds, LLC | 166K | $1M+ | SH |
Activist & 5%+ Owners
SC 13D/13G filings — investors holding 5%+ of outstanding shares
SC 13G/A · Oct 17, 2025
11.5%
5.3M shares
SC 13G/A · Feb 8, 2025
24.8%
12.5M shares
SC 13G/A · Mar 6, 2024
4.5%
2.2M shares
The Vanguard Group - 23-1945930
SC 13G/A · Feb 13, 2024
5.9%
2.8M shares
SC 13G/A · Feb 9, 2024
26.2%
13.4M shares
SC 13G/A · Jan 23, 2024
12.6%
6.0M shares
SC 13G/A · Jan 17, 2024
6.8%
3.3M shares
SC 13G/A · Feb 1, 2023
6.8%
3.3M shares
SC 13G/A · Jan 27, 2023
25.5%
13.1M shares
SC 13G/A · Jan 26, 2023
14.6%
7.0M shares
SC 13G/A · Jan 20, 2023
14.6%
7.0M shares
(entities only Federated Hermes, Inc.
SC 13G/A · Feb 14, 2022
7.2%
3.5M shares
(entities only Federated Hermes, Inc.
SC 13G/A · Feb 14, 2022
7.3%
10.2M shares
SC 13G/A · Feb 11, 2022
25.5%
12.8M shares
SC 13G/A · Jan 28, 2022
15.0%
7.2M shares