Amphastar Pharmaceuticals (AMPH)
Amphastar Pharmaceuticals on one page: short interest, daily short volume, fails to deliver, planned sales, large holders, 13F holders, financials, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as pharmaceutical preparations.
4.3M
Short interest
settlement 2026-10-15
9.8
Days to cover
+2.8 days vs prior
59.3%
Short share of volume
2026-11-02
79
Fails to deliver
settlement 2026-09-17
Thu 5 Nov
Next earnings
estimated date
-$764K
Insider flow, 90 days
0 buys, 5 sells
As of 2026-11-02.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in AMPH is 4,333,767 shares, down 661,041 shares over the last month. Over the last 48 readings it ranged from 2,967,637 shares (15 April 2025) to 5,385,239 shares (14 August 2026). At the reported average volume of 440K shares a day that is 9.8 days to cover.
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| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 4,333,767 | -1.6% | 439,800 | 9.85 |
| 2026-09-30 | 4,405,038 | -11.8% | 620,832 | 7.10 |
| 2026-09-15 | 4,994,808 | -2.7% | 464,708 | 10.75 |
| 2026-08-31 | 5,134,473 | -4.7% | 334,222 | 15.36 |
| 2026-08-14 | 5,385,239 | +9.3% | 540,569 | 9.96 |
| 2026-07-31 | 4,928,331 | +18.1% | 414,646 | 11.89 |
| 2026-07-15 | 4,174,460 | +8.6% | 374,286 | 11.15 |
| 2026-06-30 | 3,845,576 | +1.2% | 734,234 | 5.24 |
| 2026-06-15 | 3,799,584 | +1.4% | 532,703 | 7.13 |
| 2026-05-29 | 3,747,543 | -0.9% | 792,627 | 4.73 |
| 2026-05-15 | 3,779,877 | +5.4% | 802,000 | 4.71 |
| 2026-04-30 | 3,585,957 | -8.1% | 411,556 | 8.71 |
| 2026-04-15 | 3,903,290 | +10.7% | 452,484 | 8.63 |
| 2026-03-31 | 3,527,477 | -5.6% | 526,830 | 6.70 |
| 2026-03-13 | 3,738,333 | +2.2% | 725,722 | 5.15 |
| 2026-02-27 | 3,658,291 | -1.6% | 596,725 | 6.13 |
| 2026-02-13 | 3,719,566 | -3.2% | 333,044 | 11.17 |
| 2026-01-30 | 3,843,799 | +1.1% | 256,404 | 14.99 |
| 2026-01-15 | 3,803,135 | -7.2% | 383,841 | 9.91 |
| 2025-12-31 | 4,096,041 | +2.9% | 359,453 | 11.40 |
| 2025-12-15 | 3,981,951 | +19.1% | 375,076 | 10.62 |
| 2025-11-28 | 3,343,646 | -6.9% | 385,893 | 8.66 |
| 2025-11-14 | 3,589,725 | -14.4% | 546,145 | 6.57 |
| 2025-10-31 | 4,194,131 | -2.3% | 360,887 | 11.62 |
| 2025-10-15 | 4,291,932 | +7.9% | 360,143 | 11.92 |
| 2025-09-30 | 3,977,178 | -3.7% | 546,368 | 7.28 |
| 2025-09-15 | 4,130,306 | -0.6% | 411,975 | 10.03 |
| 2025-08-29 | 4,155,237 | +0.5% | 406,559 | 10.22 |
| 2025-08-15 | 4,134,257 | +2.7% | 810,532 | 5.10 |
| 2025-07-31 | 4,024,867 | +0.5% | 442,912 | 9.09 |
| 2025-07-15 | 4,005,661 | -1.4% | 484,164 | 8.27 |
| 2025-06-30 | 4,062,426 | -0.4% | 521,557 | 7.79 |
| 2025-06-13 | 4,080,346 | -0.4% | 502,123 | 8.13 |
| 2025-05-30 | 4,096,720 | +2.3% | 454,981 | 9.00 |
| 2025-05-15 | 4,005,726 | +24.9% | 653,028 | 6.13 |
| 2025-04-30 | 3,206,270 | +8.0% | 465,275 | 6.89 |
| 2025-04-15 | 2,967,637 | -13.3% | 784,370 | 3.78 |
| 2025-03-31 | 3,422,379 | -11.2% | 601,463 | 5.69 |
| 2025-03-14 | 3,852,850 | -6.7% | 636,431 | 6.05 |
| 2025-02-28 | 4,128,332 | +1.4% | 736,476 | 5.61 |
| 2025-02-14 | 4,072,042 | -1.2% | 401,414 | 10.14 |
| 2025-01-31 | 4,119,788 | -10.4% | 490,819 | 8.39 |
| 2025-01-15 | 4,600,052 | -4.5% | 657,526 | 7.00 |
| 2024-12-31 | 4,815,210 | +10.3% | 718,031 | 6.71 |
| 2024-12-13 | 4,365,856 | +5.9% | 484,849 | 9.00 |
| 2024-11-29 | 4,124,250 | -2.6% | 411,610 | 10.02 |
| 2024-11-15 | 4,235,323 | -2.5% | 476,198 | 8.89 |
| 2024-10-31 | 4,341,583 | +2.6% | 267,396 | 16.24 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of AMPH volume is 59.3%, down 14.2 points over the last five sessions. Over the last 30 readings it ranged from 40.4% (29 October 2026) to 78.0% (2 October 2026). The latest reading is 5.0 points below the 30-session average of 64.2%, on 209K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 124K | 209K | 59.3% | 908 |
| 2026-10-30 | 179K | 298K | 60.0% | 0 |
| 2026-10-29 | 50K | 124K | 40.4% | 4 |
| 2026-10-28 | 90K | 161K | 56.1% | 6 |
| 2026-10-27 | 73K | 100K | 73.2% | 0 |
| 2026-10-26 | 63K | 86K | 73.4% | 16 |
| 2026-10-23 | 147K | 211K | 69.6% | 8 |
| 2026-10-22 | 84K | 118K | 71.7% | 0 |
| 2026-10-21 | 110K | 147K | 74.7% | 0 |
| 2026-10-20 | 85K | 120K | 70.6% | 0 |
| 2026-10-19 | 82K | 123K | 67.2% | 0 |
| 2026-10-16 | 80K | 136K | 59.1% | 0 |
| 2026-10-15 | 98K | 146K | 67.1% | 0 |
| 2026-10-14 | 101K | 145K | 69.9% | 10 |
| 2026-10-13 | 86K | 125K | 68.7% | 0 |
| 2026-10-12 | 53K | 112K | 46.9% | 0 |
| 2026-10-09 | 78K | 112K | 69.8% | 200 |
| 2026-10-08 | 82K | 173K | 47.6% | 0 |
| 2026-10-07 | 105K | 188K | 55.7% | 0 |
| 2026-10-06 | 124K | 174K | 71.2% | 256 |
| 2026-10-05 | 94K | 130K | 72.4% | 0 |
| 2026-10-02 | 116K | 148K | 78.0% | 866 |
| 2026-10-01 | 140K | 207K | 67.9% | 1,755 |
| 2026-09-30 | 115K | 205K | 56.0% | 10 |
| 2026-09-29 | 157K | 272K | 57.7% | 3,600 |
| 2026-09-28 | 193K | 285K | 68.0% | 0 |
| 2026-09-25 | 97K | 160K | 60.4% | 0 |
| 2026-09-24 | 119K | 195K | 60.7% | 0 |
| 2026-09-23 | 147K | 213K | 69.1% | 0 |
| 2026-09-22 | 107K | 166K | 64.6% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 17 September 2026, the fails-to-deliver balance in AMPH is 79 shares, down 942 shares over the last settlement date. Over the last 30 readings it ranged from 1 share (11 August 2026) to 13,708 shares (20 August 2026). The latest reading sits at the bottom of that range.
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-09-17 | 79 | $23.95 | $2K |
| 2026-09-16 | 1,021 | $23.64 | $24K |
| 2026-09-14 | 787 | $23.78 | $19K |
| 2026-08-26 | 4 | $21.98 | $88 |
| 2026-08-20 | 13,708 | $21.74 | $298K |
| 2026-08-14 | 67 | $20.18 | $1K |
| 2026-08-13 | 3 | $19.98 | $60 |
| 2026-08-12 | 1,342 | $20.42 | $27K |
| 2026-08-11 | 1 | $20.31 | $20 |
| 2026-08-04 | 114 | $20.22 | $2K |
| 2026-07-29 | 1,953 | $20.15 | $39K |
| 2026-07-24 | 100 | $18.87 | $2K |
| 2026-07-23 | 182 | $19.30 | $4K |
| 2026-07-22 | 100 | $19.59 | $2K |
| 2026-07-20 | 2,810 | $19.75 | $55K |
| 2026-07-17 | 3,349 | $19.86 | $67K |
| 2026-06-30 | 1,658 | $20.71 | $34K |
| 2026-06-29 | 1,006 | $21.78 | $22K |
| 2026-06-18 | 1,792 | $19.41 | $35K |
| 2026-06-15 | 40 | $20.09 | $804 |
| 2026-05-29 | 1,749 | $19.30 | $34K |
| 2026-05-26 | 278 | $18.41 | $5K |
| 2026-05-18 | 1,181 | $16.87 | $20K |
| 2026-05-08 | 583 | $24.03 | $14K |
| 2026-05-07 | 906 | $23.90 | $22K |
| 2026-05-06 | 2,329 | $23.39 | $54K |
| 2026-05-05 | 1,855 | $22.74 | $42K |
| 2026-05-04 | 3,893 | $21.88 | $85K |
| 2026-04-30 | 3,488 | $21.63 | $75K |
| 2026-04-28 | 2,474 | $21.65 | $54K |
Insider trades
SEC Form 4, newest first. JSONInsiders at AMPH reported 5 open-market sells worth $764K in the last 90 days and no open-market buys. Latest filing: PETERS WILLIAM J (CFO, EVP & TREASURER) on 2026-09-21.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-09-21 | PETERS WILLIAM J | CFO, EVP & TREASURER | Sell | 4K | $25.00 | $103K | 169K |
| 2026-09-16 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sell | 10K | $23.94 | $239K | 169K |
| 2026-09-16 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Exercise or conversion | 10K | $13.35 | $134K | 179K |
| 2026-09-02 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sell | 3K | $23.63 | $75K | 169K |
| 2026-08-11 | PRINS RICHARD K | Director | Sell | 8K | $20.30 | $162K | 30K |
| 2026-08-07 | PETERS WILLIAM J | CFO, EVP & TREASURER | Sell | 8K | $22.48 | $184K | 173K |
| 2026-08-07 | PETERS WILLIAM J | CFO, EVP & TREASURER | Exercise or conversion | 5K | $19.79 | $100K | 181K |
| 2026-07-09 | Pierce Anthony T | Director | Grant | 8K | $0.00 | $0 | 8K |
| 2026-06-02 | Lee Howard | Director | Tax withholding | 769 | $18.45 | $14K | 159K |
| 2026-06-01 | Gaugh David Russell | Director | Grant | 8K | $0.00 | $0 | 14K |
| 2026-06-01 | Deflin Gayle | Director | Grant | 8K | $0.00 | $0 | 19K |
| 2026-06-01 | Gerst Diane G. | Director | Grant | 8K | $0.00 | $0 | 32K |
| 2026-06-01 | Lee Howard | Director | Grant | 8K | $0.00 | $0 | 160K |
| 2026-06-01 | PRINS RICHARD K | Director | Grant | 8K | $0.00 | $0 | 38K |
| 2026-06-01 | ZASLOFF MICHAEL A | Director | Grant | 8K | $0.00 | $0 | 38K |
| 2026-03-15 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 1K | $18.18 | $19K | 122K |
| 2026-03-15 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 1K | $18.18 | $22K | 172K |
| 2026-03-15 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 2K | $18.18 | $36K | 175K |
| 2026-03-15 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 3K | $18.18 | $53K | 1.2M |
| 2026-03-15 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 10K | $18.18 | $178K | 3.0M |
| 2026-03-10 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 2K | $18.91 | $35K | 123K |
| 2026-03-10 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 2K | $18.91 | $42K | 173K |
| 2026-03-10 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 3K | $18.91 | $62K | 177K |
| 2026-03-10 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 4K | $18.91 | $83K | 1.2M |
| 2026-03-10 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 15K | $18.91 | $280K | 3.0M |
| 2026-03-09 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Grant | 35K | $0.00 | $0 | 125K |
| 2026-03-09 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Grant | 39K | $0.00 | $0 | 175K |
| 2026-03-09 | PETERS WILLIAM J | CFO, EVP & TREASURER | Grant | 59K | $0.00 | $0 | 180K |
| 2026-03-09 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Grant | 72K | $0.00 | $0 | 1.3M |
| 2026-03-09 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Grant | 181K | $0.00 | $0 | 3.0M |
| 2026-03-06 | Luo Mary Z. | COO, Chief Scientist, Chairman | Tax withholding | 8K | $19.34 | $150K | 2.8M |
| 2026-03-06 | Luo Mary Z. | COO, Chief Scientist, Chairman | Tax withholding | 3K | $19.34 | $60K | 1.2M |
| 2026-03-06 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 1K | $19.34 | $22K | 89K |
| 2026-03-06 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 1K | $19.34 | $26K | 136K |
| 2026-03-06 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 2K | $19.34 | $42K | 122K |
| 2026-03-06 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 3K | $19.34 | $60K | 1.2M |
| 2026-03-06 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 8K | $19.34 | $150K | 2.8M |
| 2026-03-04 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 965 | $19.96 | $19K | 90K |
| 2026-03-04 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 1K | $19.96 | $22K | 137K |
| 2026-03-04 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 2K | $19.96 | $35K | 124K |
| 2026-03-04 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 2K | $19.96 | $49K | 1.2M |
| 2026-03-04 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 6K | $19.96 | $115K | 2.8M |
| 2025-12-17 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Sell | 10K | $26.20 | $256K | 138K |
| 2025-12-17 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Exercise or conversion | 10K | $11.33 | $111K | 148K |
| 2025-12-12 | Petersen Floyd F. | Director | Sell | 2K | $25.92 | $63K | 71K |
| 2025-12-11 | Petersen Floyd F. | Director | Sell | 2K | $25.69 | $45K | 74K |
| 2025-11-25 | PRINS RICHARD K | Director | Sell | 4K | $27.10 | $113K | 35K |
| 2025-11-25 | PRINS RICHARD K | Director | Exercise or conversion | 4K | $16.69 | $70K | 39K |
| 2025-11-13 | Petersen Floyd F. | Director | Sell | 17K | $26.49 | $442K | 76K |
| 2025-11-13 | Petersen Floyd F. | Director | Exercise or conversion | 17K | $16.69 | $278K | 92K |
| 2025-11-03 | Petersen Floyd F. | Director | Sell | 500 | $25.27 | $13K | 76K |
| 2025-10-01 | Petersen Floyd F. | Director | Sell | 500 | $27.20 | $14K | 76K |
| 2025-09-02 | Petersen Floyd F. | Director | Sell | 500 | $30.98 | $15K | 77K |
| 2025-08-01 | Petersen Floyd F. | Director | Sell | 500 | $20.83 | $10K | 77K |
| 2025-07-18 | Gaugh David Russell | Director | Grant | 6K | $0.00 | $0 | 6K |
| 2025-07-02 | Petersen Floyd F. | Director | Sell | 500 | $23.47 | $12K | 78K |
| 2025-06-13 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 200K | $13.03 | $2.6M | 2.8M |
| 2025-06-03 | Lee Howard | Director | Tax withholding | 923 | $26.01 | $24K | 152K |
| 2025-06-02 | ZASLOFF MICHAEL A | Director | Grant | 5K | $0.00 | $0 | 30K |
| 2025-06-02 | Petersen Floyd F. | Director | Sell | 500 | $25.67 | $13K | 73K |
| 2025-06-02 | Petersen Floyd F. | Director | Grant | 5K | $0.00 | $0 | 78K |
| 2025-06-02 | PRINS RICHARD K | Director | Grant | 5K | $0.00 | $0 | 35K |
| 2025-06-02 | Gerst Diane G. | Director | Grant | 5K | $0.00 | $0 | 24K |
| 2025-06-02 | Deflin Gayle | Director | Grant | 5K | $0.00 | $0 | 11K |
| 2025-06-02 | Lee Howard | Director | Grant | 5K | $0.00 | $0 | 153K |
| 2025-05-19 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 273 | $24.79 | $7K | 125K |
| 2025-05-01 | Petersen Floyd F. | Director | Sell | 500 | $24.08 | $12K | 73K |
| 2025-04-01 | Petersen Floyd F. | Director | Sell | 500 | $28.38 | $14K | 74K |
| 2025-03-17 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 3K | $27.69 | $83K | 125K |
| 2025-03-17 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 2K | $27.69 | $48K | 91K |
| 2025-03-17 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 16K | $27.69 | $447K | 2.6M |
| 2025-03-17 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 7K | $27.69 | $200K | 1.2M |
| 2025-03-17 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 2K | $27.69 | $54K | 137K |
| 2025-03-15 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 2K | $26.66 | $52K | 128K |
| 2025-03-15 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 1K | $26.66 | $27K | 93K |
| 2025-03-15 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 4K | $26.66 | $110K | 1.2M |
| 2025-03-15 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 10K | $26.66 | $260K | 2.7M |
| 2025-03-15 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 1K | $26.66 | $33K | 139K |
| 2025-03-14 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 163K | $26.66 | $4.3M | 1.2M |
| 2025-03-14 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 211K | $14.69 | $3.1M | 1.4M |
| 2025-03-14 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 226K | $26.66 | $6.0M | 2.7M |
| 2025-03-14 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 290K | $14.69 | $4.3M | 2.9M |
| 2025-03-10 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Grant | 49K | $0.00 | $0 | 1.1M |
| 2025-03-10 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Grant | 116K | $0.00 | $0 | 2.6M |
| 2025-03-10 | PETERS WILLIAM J | CFO, EVP & TREASURER | Grant | 37K | $0.00 | $0 | 130K |
| 2025-03-10 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Grant | 21K | $0.00 | $0 | 94K |
| 2025-03-10 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Grant | 25K | $0.00 | $0 | 141K |
| 2025-03-06 | Petersen Floyd F. | Director | Sell | 1K | $27.99 | $28K | 74K |
| 2025-03-06 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 3K | $28.32 | $87K | 1.1M |
| 2025-03-06 | Zhang Jack Y. | CEO & CHIEF SCIENTIFIC OFFICER | Tax withholding | 10K | $28.32 | $273K | 2.5M |
| 2025-03-06 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 1K | $28.32 | $32K | 73K |
| 2025-03-06 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 2K | $28.32 | $61K | 93K |
| 2025-03-06 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 1K | $28.32 | $38K | 116K |
| 2025-03-04 | Luo Mary Z. | COO, Chief Scientist, Chairman | Tax withholding | 6K | $27.62 | $159K | 2.5M |
| 2025-03-04 | Luo Mary Z. | COO, Chief Scientist, Chairman | Tax withholding | 2K | $27.62 | $67K | 1.1M |
| 2025-03-04 | Liawatidewi Yakob | EVP CORP ADMIN CENTER | Tax withholding | 963 | $27.62 | $27K | 74K |
| 2025-03-04 | Zhou Rong | SENIOR EVP, PRODUCTION CENTER | Tax withholding | 1K | $27.62 | $31K | 117K |
| 2025-03-04 | PETERS WILLIAM J | CFO, EVP & TREASURER | Exercise or conversion | 7K | $13.35 | $100K | 102K |
| 2025-03-04 | PETERS WILLIAM J | CFO, EVP & TREASURER | Tax withholding | 2K | $27.62 | $48K | 96K |
| 2025-03-04 | PETERS WILLIAM J | CFO, EVP & TREASURER | Sell | 4K | $27.54 | $117K | 97K |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Planned sales (Form 144)
Newest first. JSON12 Form 144 notices on file for AMPH worth $3.2M at the prices reported; 5 in the last 90 days worth $1.7M. Latest: PETERS WILLIAM J filed on 2026-09-21 to sell 4,139 shares ($103K) from 2026-09-21.
| Filed | Seller | Shares | Market value | Of outstanding | Sale from | Broker |
|---|---|---|---|---|---|---|
| 2026-09-21 | PETERS WILLIAM JOfficer | 4K | $103K | 0.010% | 2026-09-21 | UBS Financial Services, Inc. |
| 2026-09-01 | Rong ZhouVice President | 13K | $290K | 0.030% | 2026-09-01 | UBS Financial Services Inc |
| 2026-08-18 | Floyd PetersenDirector | 47K | $989K | 0.107% | 2026-08-18 | UBS Financial Services Inc |
| 2026-08-11 | Richard PrinsDirector | 8K | $162K | 0.018% | 2026-08-11 | UBS Financial Services Inc |
| 2026-08-07 | PETERS WILLIAM JOfficer | 8K | $184K | 0.019% | 2026-08-07 | UBS Financial Services, Inc. |
| 2025-12-11 | Floyd PetersenDirector | 4K | $333K | 0.009% | 2025-12-11 | UBS Financial Services Inc |
| 2025-12-10 | Floyd PetersenDirector | 2K | $43K | 0.004% | 2025-12-10 | UBS Financial Services Inc |
| 2025-11-28 | Rong ZhouOfficer | 20K | $500K | 0.044% | 2025-11-28 | UBS Financial Services Inc |
| 2025-11-25 | Richard PrinsDirector | 4K | $104K | 0.008% | 2025-11-25 | UBS Financial Services Inc |
| 2025-11-13 | Floyd PetersenDirector | 17K | $442K | 0.036% | 2025-11-13 | UBS Financial Services Inc |
| 2025-11-03 | Petersen Floyd F.Director | 500 | $13K | 0.001% | 2025-11-03 | UBS Financial Services, Inc. |
| 2025-10-01 | Petersen Floyd F.Director | 500 | $13K | 0.001% | 2025-10-01 | UBS Financial Services, Inc. |
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON2 holders report 5% or more of AMPH in their latest filing, all on Schedule 13G (passive). The largest reported stake is BlackRock, Inc. at 11.5% of the class (5,333,463 shares), filed 2025-10-17 for an event on 2025-09-30.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-07-14 | 13G | Dimensional Fund Advisors LPinvestment adviser | 2.3M | 5.2% | 2026-06-30 |
| 2026-03-26 | 13G/Ano. 5 | The Vanguard Groupinvestment adviser | 0 | 0.0% | 2026-03-13 |
| 2025-10-17 | 13G/Ano. 9 | BlackRock, Inc.parent holding company, parent holding company | 5.3M | 11.5% | 2025-09-30 |
13F holders
Tracked managers holding AMPH at their latest 13F. JSON7 of the 30 tracked managers held AMPH at their latest 13F, $39.8M in total at quarter-end prices. D. E. Shaw & Co. is the largest at $17.9M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 4 added shares and 3 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| D. E. Shaw & Co. | 2026-06-30 | 887K | $17.9M | 0.01% | +222K |
| Renaissance Technologies | 2026-06-30 | 525K | $10.6M | 0.01% | -29K |
| Two Sigma Investments | 2026-06-30 | 248K | $5.0M | 0.00% | +110K |
| AQR Capital Management | 2026-06-30 | 209K | $4.2M | 0.00% | +130K |
| Point72 Asset Management | 2026-06-30 | 55K | $1.1M | 0.00% | new |
| Millennium Management | 2026-06-30 | 32K | $642K | 0.00% | -340K |
| Citadel Advisors | 2026-06-30 | 16K | $328K | 0.00% | -49K |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
Financials
SEC XBRL, as filed. JSONIn Q2 FY 2026 (quarter ended 2026-06-30) Amphastar Pharmaceuticals reported revenue of $183.9M, up 5.4% from the same quarter a year earlier, and net income of $30.3M (0.67 diluted EPS). In FY 2025 it generated $156.1M of operating cash flow and spent $75.6M on buybacks.
- Cash
- $223.6M
- Total assets
- $1.74B
- Shares outstanding
- 42,537,944
Quarterly, last 8 quarters
| Quarter | Period end | Revenue | Net income | Margin | Diluted EPS |
|---|---|---|---|---|---|
| Q2 FY 2026 | 2026-06-30 | $183.9M | $30.3M | 16.5% | 0.67 |
| Q1 FY 2026 | 2026-03-31 | $171.2M | $6.4M | 3.8% | 0.14 |
| Q4 FY 2025derived | 2025-12-31 | $183.1M | $24.4M | 13.3% | n/a |
| Q3 FY 2025 | 2025-09-30 | $191.8M | $17.4M | 9.0% | 0.37 |
| Q2 FY 2025 | 2025-06-30 | $174.4M | $31.0M | 17.8% | 0.64 |
| Q1 FY 2025 | 2025-03-31 | $170.5M | $25.3M | 14.8% | 0.51 |
| Q4 FY 2024derived | 2024-12-31 | $186.5M | $38.0M | 20.4% | n/a |
| Q3 FY 2024 | 2024-09-30 | $191.2M | $40.4M | 21.1% | 0.78 |
Fiscal years, with buybacks and dividends
| Fiscal year | Ends | Revenue | Net income | Operating cash flow | Capex | Buybacks | Dividends |
|---|---|---|---|---|---|---|---|
| FY 2025 | 2025-12-31 | $719.9M | $98.1M | $156.1M | $34.9M | $75.6M | n/a |
| FY 2024 | 2024-12-31 | $732.0M | $159.5M | $213.4M | $41.0M | $85.5M | n/a |
| FY 2023 | 2023-12-31 | $644.4M | $137.5M | $183.5M | $38.2M | $58.1M | n/a |
| FY 2022 | 2022-12-31 | $499.0M | $91.4M | $89.2M | $24.0M | $39.9M | n/a |
| FY 2021 | 2021-12-31 | $437.8M | $62.1M | $98.0M | $27.5M | $28.9M | n/a |
Quarters are the three-month figures the company reports; a fourth quarter marked derived is the fiscal year less the three reported quarters, since companies report it only inside the 10-K. Fiscal years are the annual figures. Buybacks are the cash the company paid to repurchase its common stock in the year, not the amount authorized. Balance sheet lines are as of 2026-06-30; shares outstanding as of 2026-07-31 from the cover page.
What this page is
Amphastar Pharmaceuticals in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows Amphastar Pharmaceuticals (AMPH), SEC CIK 1297184, listed on Nasdaq, classified by the SEC as pharmaceutical preparations. The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-02.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-09-17.JSON and CSV
- Planned sales
- SEC EDGAR Form 144Source: SEC.New notices appear shortly after the SEC posts them; a notice is filed on or before the sale. Latest 2026-09-21.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-07-14.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Financials
- SEC EDGAR 10-K and 10-Q filingsSource: SEC.Weekly; values are as filed in the 10-Q and 10-K. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-08-06.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-09-21.JSON and CSV
- Company record
- EDGAR filing index for CIK 1297184Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
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Datasets
Frequently Asked Questions
How much of AMPH is sold short?
4,333,767 shares were held short at the 2026-10-15 settlement, 9.8 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is AMPH's daily short volume?
On 2026-11-02, 123,823 of the 208,878 AMPH shares reported to FINRA were sold short, 59.3% of the day's reported volume. Short volume is a flow for one day, not a position.
Does AMPH have fails to deliver?
The SEC's latest file shows 79 AMPH shares failed to deliver at settlement 2026-09-17. Fails are reported per settlement date and published twice a month with a lag.
Are AMPH insiders buying or selling?
Insiders at AMPH reported 5 open-market sells worth $764K in the last 90 days and no open-market buys. Latest filing: PETERS WILLIAM J (CFO, EVP & TREASURER) on 2026-09-21.
Have AMPH insiders filed to sell?
12 Form 144 notices on file for AMPH worth $3.2M at the prices reported; 5 in the last 90 days worth $1.7M. Latest: PETERS WILLIAM J filed on 2026-09-21 to sell 4,139 shares ($103K) from 2026-09-21.
Who owns 5% or more of AMPH?
2 holders report 5% or more of AMPH in their latest filing, all on Schedule 13G (passive). The largest reported stake is BlackRock, Inc. at 11.5% of the class (5,333,463 shares), filed 2025-10-17 for an event on 2025-09-30.
What did AMPH report last quarter?
In Q2 FY 2026 (quarter ended 2026-06-30) Amphastar Pharmaceuticals reported revenue of $183.9M, up 5.4% from the same quarter a year earlier, and net income of $30.3M (0.67 diluted EPS). In FY 2025 it generated $156.1M of operating cash flow and spent $75.6M on buybacks.
Which tracked 13F managers own AMPH?
7 of the 30 tracked 13F managers held AMPH shares at their latest filing, $39.8M in all. The largest: D. E. Shaw & Co. (887K shares, $17.9M), Renaissance Technologies (525K shares, $10.6M), Two Sigma Investments (248K shares, $5.0M), Cliff Asness's AQR Capital Management (209K shares, $4.2M), Steve Cohen's Point72 Asset Management (55K shares, $1.1M), Izzy Englander's Millennium Management (32K shares, $642K). The table above lists all 7.
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.