AMPHASTAR PHARMACEUTICALS IN (AMPH) Institutional Shareholders
AMPHASTAR PHARMACEUTICALS IN (AMPH) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $569.74M in AMPH holdings during the latest filing period.
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 $124.46M, representing an estimated gain of +18.04% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 58% 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
204
Total Reported Value
$569.74M
Largest Holder
Blackrock, Inc.
Largest Position
$105.44M
Insider Transactions (90d)
6
Latest Filing Quarter
Q2 2026
New Institutional Positions
42
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 | $124,457,928 | +$19,018,760 | +18.04% | |
| Dimensional Fund Advisors Lp | 0.01% | 2,305,107 | $46,519,189 | $54,907,649 | +$8,388,460 | +18.03% | |
| State Street Corp | 0.00% | 1,642,126 | $33,138,103 | $39,115,441 | +$5,977,338 | +18.04% | |
| Vanguard Capital Management Llc | 0.00% | 1,481,952 | $29,905,791 | $35,300,097 | +$5,394,306 | +18.04% | |
| American Century Companies Inc | 0.01% | 1,176,626 | $23,744,313 | $28,027,231 | +$4,282,918 | +18.04% | |
| Marshall Wace, Llp | 0.02% | 1,066,322 | $21,518,378 | $25,399,790 | +$3,881,412 | +18.04% | |
| Geode Capital Management, Llc | 0.00% | 969,840 | $19,575,036 | $23,101,589 | +$3,526,553 | +18.02% | |
| Fuller & Thaler Asset Management, Inc. | 0.05% | 949,238 | $19,155,615 | $22,610,849 | +$3,455,234 | +18.04% | |
| D. E. Shaw & Co., Inc. | 0.01% | 887,048 | $17,900,629 | $21,129,483 | +$3,228,854 | +18.04% | |
| Vanguard Portfolio Management Llc | 0.00% | 809,568 | $16,337,082 | $19,283,910 | +$2,946,828 | +18.04% | |
| Lsv Asset Management | 0.02% | 642,014 | $12,956,000 | $15,292,773 | +$2,336,773 | +18.04% | |
| Renaissance Technologies LLC | Jim Simons | 0.01% | 525,100 | $10,596,518 | $12,507,882 | +$1,911,364 | +18.04% |
| Goldman Sachs Group Inc | 0.00% | 505,360 | $10,198,165 | $12,037,675 | +$1,839,510 | +18.04% | |
| Systematic Financial Management Lp | 0.18% | 437,384 | $8,826,439 | $10,418,487 | +$1,592,048 | +18.04% | |
| Morgan Stanley | 0.00% | 434,840 | $8,775,081 | $10,357,889 | +$1,582,808 | +18.04% | |
| Ubs Group Ag | 0.00% | 393,110 | $7,932,960 | $9,363,880 | +$1,430,920 | +18.04% | |
| Hrt Financial Lp | 0.01% | 387,530 | $7,820,000 | $9,230,965 | +$1,410,965 | +18.04% | |
| Denali Advisors Llc | 0.76% | 375,965 | $7,586,974 | $8,955,486 | +$1,368,512 | +18.04% | |
| Northern Trust Corp | 0.00% | 370,991 | $7,486,598 | $8,837,006 | +$1,350,408 | +18.04% | |
| Bridge City Capital, Llc | 1.56% | 338,708 | $6,835,127 | $8,068,025 | +$1,232,898 | +18.04% | |
| Charles Schwab Investment Management Inc | 0.00% | 310,178 | $6,259,392 | $7,388,440 | +$1,129,048 | +18.04% | |
| Bridgeway Capital Management, Llc | 0.11% | 298,954 | $6,032,892 | $7,121,084 | +$1,088,192 | +18.04% | |
| Royce & Associates Lp | 0.05% | 294,758 | $5,948,216 | $7,021,136 | +$1,072,920 | +18.04% | |
| Two Sigma Investments, Lp | 0.00% | 248,115 | $5,006,961 | $5,910,099 | +$903,138 | +18.04% | |
| First Trust Advisors Lp | 0.00% | 246,951 | $4,983,471 | $5,882,373 | +$898,902 | +18.04% | |
| Pacer Advisors, Inc. | 0.01% | 241,181 | $4,867,000 | $5,744,931 | +$877,931 | +18.04% | |
| Bank Of New York Mellon Corp | 0.00% | 232,343 | $4,688,681 | $5,534,410 | +$845,729 | +18.04% | |
| Vanguard Fiduciary Trust Co | 0.00% | 224,478 | $4,529,966 | $5,347,066 | +$817,100 | +18.04% | |
| Aqr Capital Management Llc | 0.00% | 208,651 | $4,210,576 | $4,970,067 | +$759,491 | +18.04% | |
| Principal Financial Group Inc | 0.00% | 204,250 | $4,121,765 | $4,865,235 | +$743,470 | +18.04% | |
| New York State Common Retirement Fund | 0.00% | 181,122 | $3,655,042 | $4,314,326 | +$659,284 | +18.04% | |
| Jane Street Group, Llc | 0.00% | 178,734 | $3,606,852 | $4,257,444 | +$650,592 | +18.04% | |
| Empowered Funds, Llc | 0.02% | 162,812 | $3,285,546 | $3,878,182 | +$592,636 | +18.04% | |
| O'Shaughnessy Asset Management, Llc | 0.01% | 159,427 | $3,217,237 | $3,797,551 | +$580,314 | +18.04% | |
| Invesco Ltd. | 0.00% | 158,064 | $3,189,732 | $3,765,084 | +$575,352 | +18.04% | |
| Victory Capital Management Inc | 0.00% | 149,612 | $3,019,170 | $3,563,758 | +$544,588 | +18.04% | |
| Universal- Beteiligungs- Und Servicegesellschaft Mbh | 0.00% | 139,402 | $2,813,132 | $3,320,556 | +$507,424 | +18.04% | |
| Bank Of America Corp | 0.00% | 136,824 | $2,761,109 | $3,259,148 | +$498,039 | +18.04% | |
| Algert Global Llc | 0.03% | 131,400 | $2,651,652 | $3,129,948 | +$478,296 | +18.04% | |
| Lam Group, Inc. | 1.31% | 130,800 | $2,639,544 | $3,115,656 | +$476,112 | +18.04% | |
| Nordea Investment Management Ab | 0.00% | 126,931 | $2,558,929 | $3,023,496 | +$464,567 | +18.15% | |
| Bessemer Group Inc | 0.00% | 121,345 | $2,448,000 | $2,890,438 | +$442,438 | +18.07% | |
| Arrowstreet Capital, Limited Partnership | 0.00% | 116,653 | $2,354,058 | $2,778,674 | +$424,616 | +18.04% | |
| Public Sector Pension Investment Board | 0.01% | 116,648 | $2,353,957 | $2,778,555 | +$424,598 | +18.04% | |
| Nuveen, Llc | 0.00% | 88,397 | $1,783,852 | $2,105,617 | +$321,765 | +18.04% | |
| Vanguard Global Advisers, Llc | 0.00% | 87,639 | $1,768,555 | $2,087,561 | +$319,006 | +18.04% | |
| Exchange Traded Concepts, Llc | 0.01% | 87,054 | $1,756,750 | $2,073,626 | +$316,876 | +18.04% | |
| Rhumbline Advisers | 0.00% | 80,454 | $1,623,544 | $1,916,414 | +$292,870 | +18.04% | |
| Squarepoint Ops Llc | 0.00% | 78,795 | $1,590,083 | $1,876,897 | +$286,814 | +18.04% | |
| Legal & General Group Plc | 0.00% | 78,281 | $1,579,712 | $1,864,653 | +$284,941 | +18.04% |
Frequently asked questions about AMPH
Who owns the most AMPH stock?
The largest holders of AMPH are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for AMPHASTAR PHARMACEUTICALS IN (AMPH).
Is AMPH widely held by superinvestors?
Many widely followed stocks like AMPH appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly AMPH is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.