AMPH Institutional Ownership & Shareholders
AMPHASTAR PHARMACEUTICALS IN (AMPH) is currently held by 211 institutional investors tracked by InsiderSet, with a combined reported market value of approximately $580.02M based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.
Blackrock, Inc. is currently the largest disclosed institutional shareholder of AMPH tracked by InsiderSet, reporting ownership valued at approximately $105.44M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $141.23M, representing an estimated gain of +33.94% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 57% of the total disclosed AMPH value among the investors covered in this analysis. Major shareholders include Blackrock, Inc., Dimensional Fund Advisors Lp, State Street Corp, and several other long-term asset managers with concentrated positions in AMPHASTAR PHARMACEUTICALS IN (AMPH).
This page ranks the largest institutional AMPH shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
211
Total Reported Value
$580.02M
Largest Holder
Blackrock, Inc.
Largest Position
$105.44M
Insider Transactions (90d)
6
Latest Filing Quarter
Q2 2026
New Institutional Positions
43
Funds Exiting Positions
1
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Blackrock, Inc. | 0.00% | 5,224,934 | $105,439,168 | $141,229,966 | +$35,790,798 | +33.94% | |
| Dimensional Fund Advisors Lp | 0.01% | 2,305,107 | $46,519,189 | $62,307,042 | +$15,787,853 | +33.94% | |
| State Street Corp | 0.00% | 1,642,126 | $33,138,103 | $44,386,666 | +$11,248,563 | +33.94% | |
| Vanguard Capital Management Llc | 0.00% | 1,481,952 | $29,905,791 | $40,057,163 | +$10,151,372 | +33.94% | |
| American Century Companies Inc | 0.01% | 1,176,626 | $23,744,313 | $31,804,201 | +$8,059,888 | +33.94% | |
| Marshall Wace, Llp | 0.02% | 1,066,322 | $21,518,378 | $28,822,684 | +$7,304,306 | +33.94% | |
| Geode Capital Management, Llc | 0.00% | 969,840 | $19,575,036 | $26,214,775 | +$6,639,739 | +33.92% | |
| Fuller & Thaler Asset Management, Inc. | 0.05% | 949,238 | $19,155,615 | $25,657,903 | +$6,502,288 | +33.94% | |
| D. E. Shaw & Co., Inc. | 0.01% | 887,048 | $17,900,629 | $23,976,907 | +$6,076,278 | +33.94% | |
| Vanguard Portfolio Management Llc | 0.00% | 809,568 | $16,337,082 | $21,882,623 | +$5,545,541 | +33.94% | |
| Lsv Asset Management | 0.02% | 642,014 | $12,956,000 | $17,353,638 | +$4,397,638 | +33.94% | |
| Renaissance Technologies LLC | Jim Simons | 0.01% | 525,100 | $10,596,518 | $14,193,453 | +$3,596,935 | +33.94% |
| Goldman Sachs Group Inc | 0.00% | 505,360 | $10,198,165 | $13,659,881 | +$3,461,716 | +33.94% | |
| Bridge City Capital, Llc | 2.07% | 383,901 | $9,908,485 | $10,376,844 | +$468,359 | +4.73% | |
| Systematic Financial Management Lp | 0.18% | 437,384 | $8,826,439 | $11,822,490 | +$2,996,051 | +33.94% | |
| Morgan Stanley | 0.00% | 434,840 | $8,775,081 | $11,753,725 | +$2,978,644 | +33.94% | |
| Ubs Group Ag | 0.00% | 393,110 | $7,932,960 | $10,625,763 | +$2,692,803 | +33.94% | |
| Hrt Financial Lp | 0.01% | 387,530 | $7,820,000 | $10,474,936 | +$2,654,936 | +33.95% | |
| Denali Advisors Llc | 0.76% | 375,965 | $7,586,974 | $10,162,334 | +$2,575,360 | +33.94% | |
| Northern Trust Corp | 0.00% | 370,991 | $7,486,598 | $10,027,887 | +$2,541,289 | +33.94% | |
| Principal Financial Group Inc | 0.00% | 261,465 | $6,748,412 | $7,067,399 | +$318,987 | +4.73% | |
| Charles Schwab Investment Management Inc | 0.00% | 310,178 | $6,259,392 | $8,384,111 | +$2,124,719 | +33.94% | |
| Bridgeway Capital Management, Llc | 0.11% | 298,954 | $6,032,892 | $8,080,727 | +$2,047,835 | +33.94% | |
| Royce & Associates Lp | 0.05% | 294,758 | $5,948,216 | $7,967,309 | +$2,019,093 | +33.94% | |
| Two Sigma Investments, Lp | 0.00% | 248,115 | $5,006,961 | $6,706,548 | +$1,699,587 | +33.94% | |
| First Trust Advisors Lp | 0.00% | 246,951 | $4,983,471 | $6,675,086 | +$1,691,615 | +33.94% | |
| Pacer Advisors, Inc. | 0.01% | 241,181 | $4,867,000 | $6,519,122 | +$1,652,122 | +33.95% | |
| Bank Of New York Mellon Corp | 0.00% | 232,343 | $4,688,681 | $6,280,231 | +$1,591,550 | +33.94% | |
| Vanguard Fiduciary Trust Co | 0.00% | 224,478 | $4,529,966 | $6,067,640 | +$1,537,674 | +33.94% | |
| Aqr Capital Management Llc | 0.00% | 208,651 | $4,210,576 | $5,639,837 | +$1,429,261 | +33.94% | |
| New York State Common Retirement Fund | 0.00% | 181,122 | $3,655,042 | $4,895,728 | +$1,240,686 | +33.94% | |
| Jane Street Group, Llc | 0.00% | 178,734 | $3,606,852 | $4,831,180 | +$1,224,328 | +33.94% | |
| Lam Group, Inc. | 1.70% | 130,800 | $3,375,948 | $3,535,524 | +$159,576 | +4.73% | |
| Empowered Funds, Llc | 0.02% | 162,812 | $3,285,546 | $4,400,808 | +$1,115,262 | +33.94% | |
| O'Shaughnessy Asset Management, Llc | 0.01% | 159,427 | $3,217,237 | $4,309,312 | +$1,092,075 | +33.94% | |
| Invesco Ltd. | 0.00% | 158,064 | $3,189,732 | $4,272,470 | +$1,082,738 | +33.94% | |
| Victory Capital Management Inc | 0.00% | 149,612 | $3,019,170 | $4,044,012 | +$1,024,842 | +33.94% | |
| Universal- Beteiligungs- Und Servicegesellschaft Mbh | 0.00% | 139,402 | $2,813,132 | $3,768,036 | +$954,904 | +33.94% | |
| Bank Of America Corp | 0.00% | 136,824 | $2,761,109 | $3,698,353 | +$937,244 | +33.94% | |
| Algert Global Llc | 0.03% | 131,400 | $2,651,652 | $3,551,742 | +$900,090 | +33.94% | |
| Nordea Investment Management Ab | 0.00% | 126,931 | $2,558,929 | $3,430,945 | +$872,016 | +34.08% | |
| Bessemer Group Inc | 0.00% | 121,345 | $2,448,000 | $3,279,955 | +$831,955 | +33.99% | |
| Arrowstreet Capital, Limited Partnership | 0.00% | 116,653 | $2,354,058 | $3,153,131 | +$799,073 | +33.94% | |
| Public Sector Pension Investment Board | 0.01% | 116,648 | $2,353,957 | $3,152,995 | +$799,038 | +33.94% | |
| Creative Planning | 0.00% | 81,863 | $2,112,884 | $2,212,757 | +$99,873 | +4.73% | |
| Assetmark, Inc | 0.00% | 79,124 | $2,042,190 | $2,138,722 | +$96,532 | +4.73% | |
| Nuveen, Llc | 0.00% | 88,397 | $1,783,852 | $2,389,371 | +$605,519 | +33.94% | |
| Vanguard Global Advisers, Llc | 0.00% | 87,639 | $1,768,555 | $2,368,882 | +$600,327 | +33.94% | |
| Rhumbline Advisers | 0.00% | 80,454 | $1,623,544 | $2,174,672 | +$551,128 | +33.95% | |
| Squarepoint Ops Llc | 0.00% | 78,795 | $1,590,083 | $2,129,829 | +$539,746 | +33.94% |
Frequently asked questions about AMPH
Who are the largest institutional holders of AMPH?
The largest institutional holders of AMPH reported in the latest SEC Form 13F filings include Blackrock, Inc., Dimensional Fund Advisors Lp, State Street Corp, Vanguard Capital Management Llc, and American Century Companies Inc. InsiderSet ranks institutional holders by their latest reported AMPH position.
What is AMPH institutional ownership?
This page tracks AMPH positions reported by institutional investment managers through SEC Form 13F. AMPHASTAR PHARMACEUTICALS IN (AMPH) institutional ownership on InsiderSet reflects disclosed 13F holdings among the managers we analyze, not every shareholder of the stock.
How many institutions own AMPH?
InsiderSet currently tracks 211 institutional managers reporting AMPH holdings in the latest available 13F data. This count reflects institutions included in the SEC Form 13F filings analyzed by InsiderSet and should not be interpreted as the total number of AMPH shareholders.
How much AMPH stock do institutions own?
Institutional investment managers disclosed approximately $580.02M in AMPH holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value.
When was AMPH institutional ownership last updated?
The latest AMPH institutional ownership data on InsiderSet is based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time institutional holdings.
Are institutional AMPH holdings real-time?
No. Form 13F data is not real-time. It represents positions reported by institutional investment managers as of the end of the reporting quarter. An institution may have changed its AMPH position after the reporting date.
Are institutions buying or selling AMPH?
Institutional buying and selling can be analyzed by comparing AMPH positions across consecutive 13F reporting periods. InsiderSet's AMPH Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View AMPH ownership changes.
How has AMPH institutional ownership changed over time?
InsiderSet tracks AMPH institutional holdings across multiple 13F reporting periods, allowing investors to compare institutional holder counts, reported value, and reported shares over time.