Who owns AMPH?
Institutional ownership of Amphastar Pharmaceuticals Inc. from Form 13F, Q2 2026
210 institutional managers reported holding Amphastar Pharmaceuticals Inc. (AMPH) in Form 13F filings for Q2 2026, with 28,333,453 shares worth $572M. The largest reported holder was BlackRock, Inc. Managers that filed both quarters cut a net 3,752,019 shares (-11.7%). 31 opened new positions and 33 sold out.
- Funds holding
- 210
- Value held
- $572M
- New / sold out
- 31 / 33
- Net shares, same filers
- -11.7%
Holdings as of June 30, 2026, the end of Q2 2026. Managers have 45 days after a quarter ends to file Form 13F (by August 14, 2026 for Q2 2026), so positions may have changed since.
Largest holders of AMPH
| Fund | Value | Share of 13F holdings | Shares | Move |
|---|---|---|---|---|
| BlackRock, Inc. | $105M | 18.4% | 5,224,934 | Trimmed |
| Dimensional Fund Advisors LP | $46.5M | 8.1% | 2,305,107 | Added |
| State Street Corp | $33.1M | 5.8% | 1,642,126 | Added |
| Vanguard Capital Management LLC | $29.9M | 5.2% | 1,481,952 | Trimmed |
| American Century Companies Inc | $23.7M | 4.2% | 1,176,626 | Added |
| Marshall Wace, LLP | $21.5M | 3.8% | 1,066,322 | Added |
| Geode Capital Management, LLC | $19.6M | 3.4% | 969,840 | Trimmed |
| Fuller & Thaler Asset Management, Inc. | $19.2M | 3.4% | 949,238 | Trimmed |
| D. E. Shaw & Co., Inc. | $17.9M | 3.1% | 887,048 | Added |
| Vanguard Portfolio Management LLC | $16.3M | 2.9% | 809,568 | Added |
| LSV Asset Management | $13.0M | 2.3% | 642,014 | Trimmed |
| Renaissance Technologies LLC | $10.6M | 1.9% | 525,100 | Trimmed |
| Goldman Sachs Group Inc | $10.2M | 1.8% | 505,360 | Added |
| Systematic Financial Management LP | $8.8M | 1.5% | 437,384 | Trimmed |
| Morgan Stanley | $8.8M | 1.5% | 434,840 | Added |
| UBS Group AG | $7.9M | 1.4% | 393,110 | Trimmed |
| HRT Financial LP | $7.8M | 1.4% | 387,530 | Added |
| Denali Advisors LLC | $7.6M | 1.3% | 375,965 | Added |
| Northern Trust Corp | $7.5M | 1.3% | 370,991 | Trimmed |
| Bridge City Capital, LLC | $6.8M | 1.2% | 338,708 | Added |
| Charles Schwab Investment Management Inc | $6.3M | 1.1% | 310,178 | Trimmed |
| Bridgeway Capital Management, LLC | $6.0M | 1.1% | 298,954 | Trimmed |
| Royce & Associates LP | $5.9M | 1.0% | 294,758 | Trimmed |
| Two Sigma Investments, LP | $5.0M | 0.9% | 248,115 | Added |
| First Trust Advisors LP | $5.0M | 0.9% | 246,951 | Added |
Share of 13F holdings is each fund's shares as a share of the 28,333,453 AMPH shares all 13F filers reported, not of shares outstanding.
Biggest buyers in Q2 2026
- HRT Financial LP Added+$6.7M
- Dimensional Fund Advisors LP Added+$5.6M
- Pacer Advisors, Inc. New+$4.9M
- D. E. Shaw & Co., Inc. Added+$4.5M
- Goldman Sachs Group Inc Added+$3.6M
- American Century Companies Inc Added+$3.2M
- AQR Capital Management LLC Added+$2.6M
- Two Sigma Investments, LP Added+$2.2M
- Denali Advisors LLC Added+$2.2M
- First Trust Advisors LP Added+$1.9M
Biggest sellers in Q2 2026
- TD Asset Management Inc Sold out-$30.2M
- Boston Trust Walden Corp Sold out-$18.5M
- Epoch Investment Partners, Inc. Sold out-$17.6M
- Invesco Ltd. Trimmed-$9.0M
- Fuller & Thaler Asset Management, Inc. Trimmed-$9.0M
- Millennium Management LLC Trimmed-$6.9M
- Arrowstreet Capital, Limited Partnership Trimmed-$4.2M
- BlackRock, Inc. Trimmed-$4.0M
- Rice Hall James & Associates, LLC Sold out-$3.7M
- Voloridge Investment Management, LLC Trimmed-$2.4M
The change in shares since the quarter before, adjusted for stock splits and priced at the Q2 2026 value per share. Funds bought $58.6M and sold $132M; 62 added and 74 trimmed.
Schedule 13D and 13G filings on AMPH
Owners of more than 5% must file within days, so these can be newer than the 13F data.
- 2026-07-14DIMENSIONAL FUND ADVISORS LP SCHEDULE 13G filed by Amphastar Pharmaceuticals Inc.Schedule 13G
Questions about AMPH ownership
- Who owns AMPH stock?
- 210 institutional investment managers reported AMPH positions in their Form 13F filings for Q2 2026, holding 28,333,453 shares worth $572M in total. BlackRock, Inc. reported the largest position.
- Are funds buying or selling AMPH?
- In Q2 2026, 31 managers opened new AMPH positions, 62 added, 74 trimmed and 33 sold out. Managers that filed in both quarters sold a net 3,752,019 shares.
- How current is this AMPH institutional ownership data?
- It covers holdings as of the end of Q2 2026. Managers have 45 days after the quarter ends to file Form 13F (by August 14, 2026 for Q2 2026), so positions may have changed since.
From the SEC's Form 13F data sets for Q2 2026: every 13F holdings report, matched to AMPH by CUSIP. Options are left out. AMPH news and filings · AMPH insider trades · Top funds