AMPHASTAR PHARMACEUTICALS IN AMPH
COM · Common Stock · CUSIP 03209R103 · ISIN US03209R1032
Publicly traded American pharmaceutical company
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersRancho Cucamonga, CA
- Founded1996
- Websiteamphastar.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($2.5m this quarter). Holder counts are more reliable. Shares outstanding: 46.5m as of 2025-08-01, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $22.98. Options: 4 managers hold calls ($447.1k notional), 5 hold puts ($380.7k).
Trends to Q2 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 208 |
| Q4 2022 | 212 |
| Q1 2023 | 218 |
| Q2 2023 | 246 |
| Q3 2023 | 256 |
| Q4 2023 | 277 |
| Q1 2024 | 271 |
| Q2 2024 | 269 |
| Q3 2024 | 279 |
| Q4 2024 | 264 |
| Q1 2025 | 242 |
| Q2 2025 | 246 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q3 2023 | 128 | 121 |
| Q4 2023 | 137 | 115 |
| Q1 2024 | 133 | 151 |
| Q2 2024 | 133 | 139 |
| Q3 2024 | 137 | 125 |
| Q4 2024 | 112 | 149 |
| Q1 2025 | 109 | 144 |
| Q2 2025 | 133 | 113 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2024 | $3.9m | $1.1m | 0.29 |
| Q4 2024 | $1.0m | $318.3k | 0.31 |
| Q1 2025 | $637.0k | $336.3k | 0.53 |
| Q2 2025 | $447.1k | $380.7k | 0.85 |
Biggest buyers
| ROYAL BANK OF CANADA | Added | +611.4k |
| DIMENSIONAL FUND ADVISORS LP | Added | +270.5k |
| D. E. Shaw & Co., Inc. | Added | +264.7k |
| VANGUARD GROUP INC | Added | +264.0k |
| Qube Research & Technologies Ltd | Added | +210.5k |
| CX Institutional | Added | +181.1k |
| MORGAN STANLEY | Added | +159.1k |
| CITADEL ADVISORS LLC | Added | +136.4k |
| JANE STREET GROUP, LLC | Added | +113.4k |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC | Added | +109.5k |
Biggest sellers
| FEDERATED HERMES, INC. | Reduced | -573.9k |
| BlackRock, Inc. | Reduced | -478.9k |
| Boston Partners | Sold out | -423.1k |
| Granite Investment Partners, LLC | Sold out | -375.8k |
| ExodusPoint Capital Management, LP | Reduced | -310.8k |
| PRICE T ROWE ASSOCIATES INC /MD/ | Reduced | -267.9k |
| MILLENNIUM MANAGEMENT LLC | Reduced | -249.6k |
| MARSHALL WACE, LLP | Reduced | -183.0k |
| TD Asset Management Inc | Reduced | -177.2k |
| NORTHERN TRUST CORP | Reduced | -173.3k |
Biggest calls
| CITADEL ADVISORS LLC | Reduced | $420.2k18.3k shares |
| GROUP ONE TRADING LLC | New | $23.0k1.0k shares |
| SIMPLEX TRADING, LLC | Reduced | $4.0k200 shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Biggest puts
| CITADEL ADVISORS LLC | Added | $282.4k12.3k shares |
| SIMPLEX TRADING, LLC | New | $57.0k2.5k shares |
| GROUP ONE TRADING LLC | New | $34.4k1.5k shares |
| WOLVERINE ASSET MANAGEMENT LLC | New | $6.9k300 shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| Zhang Jack Y. 13G · exempt (held before listing) filed 2025-02-07 | 24.8% |
| BlackRock, Inc. 13G · institution filed 2025-10-17 | 11.5% |
| DIMENSIONAL FUND ADVISORS LP 13G · institution new · filed 2026-07-14 | 5.2% |
Fell to 5% or below in the last year: VANGUARD GROUP INC (0.0%, 2026-03-26)
Insider purchases and sales in Q2 2025
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q3 2023 | 0 | — | 4 | $5.7m | $3.1m |
| Q4 2023 | 0 | — | 5 | $4.6m | $3.4m |
| Q1 2024 | 0 | — | 4 | $21.5m | $20.9m |
| Q2 2024 | 0 | — | 2 | $335.3k | $211.1k |
| Q3 2024 | 0 | — | 4 | $1.7m | $454.8k |
| Q4 2024 | 0 | — | 4 | $2.3m | $657.9k |
| Q1 2025 | 0 | — | 2 | $144.5k | $144.5k |
| Q2 2025 | 0 | — | 1 | $39.1k | $39.1k |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2025-06-02 | Petersen Floyd F. Director | Sold plan | $12.8k500 shares |
| 2025-05-01 | Petersen Floyd F. Director | Sold plan | $12.0k500 shares |
| 2025-04-01 | Petersen Floyd F. Director | Sold plan | $14.2k500 shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q2 2025
| Manager | Shares | Change |
|---|---|---|
| BlackRock, Inc. 0.00% of their portfolio | 5.7m $130.2m | Reduced -478.9k |
| VANGUARD GROUP INC 0.00% of their portfolio | 2.7m $61.7m | Added +264.0k |
| TD Asset Management Inc 0.04% of their portfolio | 2.0m $46.7m | Reduced -177.2k |
| DIMENSIONAL FUND ADVISORS LP 0.01% of their portfolio | 1.6m $37.4m | Added +270.5k |
| STATE STREET CORP 0.00% of their portfolio | 1.6m $36.2m | Reduced -28.4k |
| FULLER & THALER ASSET MANAGEMENT, INC. 0.11% of their portfolio | 1.3m $29.0m | Added +174 |
| Epoch Investment Partners, Inc. 0.15% of their portfolio | 1.2m $28.5m | Reduced -19.9k |
| Boston Trust Walden Corp 0.19% of their portfolio | 1.2m $27.0m | Reduced -39.2k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 973.2k $22.3m | Added +18.2k |
| MARSHALL WACE, LLP 0.02% of their portfolio | 848.7k $19.5m | Reduced -183.0k |
| MORGAN STANLEY 0.00% of their portfolio | 681.2k $15.6m | Added +159.1k |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 637.4k $14.6m | Added +611.4k |
| MILLENNIUM MANAGEMENT LLC 0.01% of their portfolio | 619.0k $14.2m | Reduced -249.6k |
| RENAISSANCE TECHNOLOGIES LLC 0.02% of their portfolio | 576.5k $13.2m | Added +81.5k |
| Qube Research & Technologies Ltd 0.01% of their portfolio | 469.5k $10.8m | Added +210.5k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 421.1k $9.7m | Reduced -173.3k |
| Invesco Ltd. 0.00% of their portfolio | 387.0k $8.9m | Added +27.8k |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC 0.03% of their portfolio | 365.9k $8.4m | Added +95.8k |
| SYSTEMATIC FINANCIAL MANAGEMENT LP 0.22% of their portfolio | 359.3k $8.2m | Added +32.8k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 356.2k $8.2m | Reduced -50.5k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 346.8k $8.0m | Added +20.6k |
| Pacer Advisors, Inc. 0.02% of their portfolio | 326.1k $7.5m | Reduced -153.3k |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC 0.03% of their portfolio | 325.5k $7.5m | Added +109.5k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 314.8k $7.2m | Added +48.7k |
| D. E. Shaw & Co., Inc. 0.01% of their portfolio | 293.9k $6.7m | Added +264.7k |
| CITADEL ADVISORS LLC 0.01% of their portfolio | 292.3k $6.7m | Added +136.4k |
| ROYCE & ASSOCIATES LP 0.07% of their portfolio | 283.2k $6.5m | Added +35.3k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 273.3k $6.3m | Reduced -267.9k |
| Balyasny Asset Management L.P. 0.01% of their portfolio | 266.3k $6.1m | Added +104.2k |
| CX Institutional 0.21% of their portfolio | 263.3k $6.0m | Added +181.1k |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 233.2k $5.4m | Reduced -74.8k |
| PRINCIPAL FINANCIAL GROUP INC 0.00% of their portfolio | 219.0k $5.0m | Added +6.4k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 169.8k $3.9m | Added +14.7k |
| JANE STREET GROUP, LLC 0.01% of their portfolio | 160.1k $3.7m | Added +113.4k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 158.1k $3.6m | Added +91.2k |
| Trexquant Investment LP 0.04% of their portfolio | 155.2k $3.6m | Added +63.9k |
| NORDEA INVESTMENT MANAGEMENT AB 0.00% of their portfolio | 152.0k $3.5m | Added +1.1k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 145.1k $3.3m | Added +38.4k |
| Bridge City Capital, LLC 0.89% of their portfolio | 138.6k $3.2m | Added +22.8k |
| LAM GROUP, INC. 2.01% of their portfolio | 130.8k $3.0m | Unchanged |
| Public Sector Pension Investment Board 0.01% of their portfolio | 125.4k $2.9m | Added +6.5k |
| ALGERT GLOBAL LLC 0.06% of their portfolio | 124.3k $2.9m | Added +107.0k |
| RAYMOND JAMES FINANCIAL INC 0.00% of their portfolio | 117.1k $2.7m | Added +87.4k |
| SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC 0.06% of their portfolio | 101.6k $2.3m | Reduced -13.5k |
| Legal & General Group Plc 0.00% of their portfolio | 101.2k $2.3m | Reduced -422 |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 95.3k $2.2m | Added +6.3k |
| TWO SIGMA ADVISERS, LP 0.00% of their portfolio | 95.2k $2.2m | Added +10.5k |
| FIRST TRUST ADVISORS LP 0.00% of their portfolio | 94.3k $2.2m | Added +76.5k |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio | 93.7k $2.2m | Added +14.6k |
| TWINBEECH CAPITAL LP 0.05% of their portfolio | 88.5k $2.0m | Added +44.5k |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.05% of their portfolio | 85.1k $2.0m | New |
| Empowered Funds, LLC 0.02% of their portfolio | 85.1k $2.0m | New |
| BARCLAYS PLC 0.00% of their portfolio | 82.1k $1.9m | Added +15.1k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio | 81.2k $1.9m | New |
| Nuveen, LLC 0.00% of their portfolio | 81.1k $1.9m | Reduced -14.5k |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 80.1k $1.8m | Added +4.8k |
| VICTORY CAPITAL MANAGEMENT INC 0.00% of their portfolio | 76.9k $1.8m | Reduced -4.2k |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 75.8k $1.7m | Added +22.2k |
| Swiss National Bank 0.00% of their portfolio | 72.6k $1.7m | Reduced -1.9k |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 71.7k $1.6m | Added +63.7k |
| UBS Group AG 0.00% of their portfolio | 66.8k $1.5m | Reduced -22.5k |
| Jump Financial, LLC 0.02% of their portfolio | 63.3k $1.5m | New |
| Quantbot Technologies LP 0.04% of their portfolio | 61.0k $1.4m | Added +39.8k |
| GSA CAPITAL PARTNERS LLP 0.09% of their portfolio | 57.1k $1.3m | Added +11.8k |
| SteelPeak Wealth, LLC 0.05% of their portfolio | 55.8k $1.3m | Unchanged |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio | 54.6k $1.3m | Reduced -16.1k |
| Engineers Gate Manager LP 0.02% of their portfolio | 53.3k $1.2m | Added +14.8k |
| Aurora Investment Counsel 0.64% of their portfolio | 53.3k $1.2m | Reduced -828 |
| INTECH INVESTMENT MANAGEMENT LLC 0.01% of their portfolio | 51.1k $1.2m | Reduced -9.2k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 50.6k $1.2m | Unchanged |
| Brevan Howard Capital Management LP 0.01% of their portfolio | 48.9k $1.1m | Added +40.3k |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 48.4k $1.1m | Reduced -33.2k |
| ASSETMARK, INC 0.00% of their portfolio | 43.8k $1.0m | Added +3.2k |
| LSV ASSET MANAGEMENT 0.00% of their portfolio | 43.2k $992.0k | Unchanged |
| Creative Planning 0.00% of their portfolio | 42.6k $978.6k | Added +22.5k |
| CITIGROUP INC 0.00% of their portfolio | 42.2k $969.4k | Reduced -35.5k |
| HRT FINANCIAL LP 0.01% of their portfolio | 42.1k $966.0k | Reduced -44.3k |
| PRUDENTIAL FINANCIAL INC 0.00% of their portfolio | 42.0k $1.7m | Added +4.3k |
| CAPITAL FUND MANAGEMENT S.A. 0.01% of their portfolio | 40.6k $931.5k | New |
| O'SHAUGHNESSY ASSET MANAGEMENT, LLC 0.01% of their portfolio | 40.3k $925.5k | New |
| Susquehanna Portfolio Strategies, LLC 0.02% of their portfolio | 39.6k $908.4k | New |
| Edgestream Partners, L.P. 0.02% of their portfolio | 37.1k $852.1k | New |
| Legato Capital Management LLC 0.10% of their portfolio | 36.1k $827.9k | Added +6.4k |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 35.9k $823.7k | Reduced -492 |
| Arkadios Wealth Advisors 0.02% of their portfolio | 35.2k $807.3k | Added +1.2k |
| Polaris Capital Management, LLC 0.05% of their portfolio | 35.1k $805.9k | Added +4.3k |
| ARISTEIA CAPITAL, L.L.C. 0.02% of their portfolio | 33.8k $776.9k | Unchanged |
| Dynamic Technology Lab Private Ltd 0.10% of their portfolio | 33.3k $765.0k | New |
| ExodusPoint Capital Management, LP 0.01% of their portfolio | 32.4k $745.0k | Reduced -310.8k |
| CANADA LIFE ASSURANCE Co 0.00% of their portfolio | 30.2k $694.0k | Reduced -1.0k |
| DANSKE BANK A/S 0.00% of their portfolio | 29.9k $686.5k | New |
| AlphaQuest LLC 0.07% of their portfolio | 28.9k $663.1k | Added +17.3k |
| Illumine Investment Management, LLC 0.50% of their portfolio | 27.1k $622.8k | Added +596 |
| Thrivent Financial for Lutherans 0.00% of their portfolio | 27.0k $621.0k | Reduced -511 |
| Advisor OS, LLC 0.06% of their portfolio | 25.4k $583.3k | Unchanged |
| STATE OF WISCONSIN INVESTMENT BOARD 0.00% of their portfolio | 25.3k $581.6k | Reduced -260 |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 25.2k $578.1k | Reduced -5.7k |
| MARTINGALE ASSET MANAGEMENT L P 0.01% of their portfolio | 24.5k $563.5k | Unchanged |
| SG Americas Securities, LLC 0.00% of their portfolio | 24.4k $561.0k | New |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 24.4k $560.1k | Reduced -5.0k |