Latest Period
Q1 2026
Security Snapshot
Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH) Institutional Ownership
CUSIP: 03209R103
13F Institutional Holders and Ownership History from Q2 2014 to Q1 2026
Institutions Reporting
213
Shares (Excl. Options)
32,342,484
Price
$19.59
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- Security type / class
- Equity / Common Stock
- Symbol
- AMPH on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 32,342,484
- Total 13F value
- $633,964,637
- Portfolio coverage rank
- 0%
- Share change
- -1,159,202
- Value change
- -$32,492,122
- Number of holders
- 213
- Underlying class
- Common Stock
- Shares outstanding
- 46,377,939
- SEC-reported price per share
- $19.30
- Insider filing price
- $19.30
Latest holder snapshot
5 signals
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Issuer context
Names, identifiers, and filing context for this profile.
3 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- AMPH - Amphastar Pharmaceuticals, Inc. - Common Stock is tracked under CUSIP 03209R103.
- 213 institutions reported positions in Q1 2026.
- 2 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 233 to 213 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $898,637,402 to $633,964,637.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 213 institutions filings for Q1 2026.
Security key
03209R103
Latest holder period
Q1 2026
13F holders
213
13D/G owners
2
CIK / CUSIP context first
Open Q1 2026 holders
AMPH full holder history
Amphastar Pharmaceuticals, Inc. SEC filings
Amphastar Pharmaceuticals, Inc. company facts
Amphastar Pharmaceuticals, Inc. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 03209R103:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
2
Security
AMPH
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| Zhang Jack Y. | 25% | $301,456,363 | 12,524,153 | Jack Y. Zhang | 31 Dec 2024 | |||
| BlackRock, Inc. | 12% | $142,136,789 | 5,333,463 | BlackRock, Inc. | 30 Sep 2025 |
As of 31 Mar 2026, 213 institutional investors reported holding 32,342,484 shares of Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH). This represents 70% of the company’s total 46,377,939 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
54%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| BlackRock, Inc. | 12% | 5,421,343 | -0.74% | 0% | $106,204,108 |
| DIMENSIONAL FUND ADVISORS LP | 4.4% | 2,027,947 | +13% | 0.01% | $39,726,234 |
| STATE STREET CORP | 3.5% | 1,607,515 | +4.9% | 0% | $31,491,219 |
| VANGUARD CAPITAL MANAGEMENT LLC | 3.3% | 1,543,655 | 0% | 0% | $30,240,201 |
| TD Asset Management Inc | 3.3% | 1,541,044 | -21% | 0.02% | $30,189,052 |
| FULLER & THALER ASSET MANAGEMENT, INC. | 3% | 1,395,139 | +0.05% | 0.09% | $27,330,780 |
| MARSHALL WACE, LLP | 2.2% | 1,025,640 | -17% | 0.02% | $20,092,287 |
| AMERICAN CENTURY COMPANIES INC | 2.2% | 1,017,538 | +53% | 0.01% | $19,933,570 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.1% | 976,650 | +10% | 0% | $19,135,848 |
| Boston Trust Walden Corp | 2% | 944,789 | -13% | 0.15% | $18,508,417 |
| Epoch Investment Partners, Inc. | 1.9% | 898,895 | -20% | 0.11% | $17,609,353 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 1.7% | 787,816 | 0% | 0% | $15,433,315 |
| D. E. Shaw & Co., Inc. | 1.4% | 665,542 | +19% | 0.01% | $13,037,968 |
| LSV ASSET MANAGEMENT | 1.4% | 651,714 | +491% | 0.03% | $12,767,000 |
| Invesco Ltd. | 1.3% | 604,774 | +21% | 0% | $11,847,522 |
| RENAISSANCE TECHNOLOGIES LLC | 1.2% | 553,900 | +1.7% | 0.02% | $10,850,901 |
| SYSTEMATIC FINANCIAL MANAGEMENT LP | 0.98% | 452,898 | +4% | 0.2% | $8,872,287 |
| MORGAN STANLEY | 0.91% | 420,337 | -29% | 0% | $8,234,414 |
| UBS Group AG | 0.91% | 420,263 | +64% | 0% | $8,232,952 |
| ROYCE & ASSOCIATES LP | 0.88% | 406,175 | +15% | 0.08% | $7,956,968 |
| NORTHERN TRUST CORP | 0.8% | 372,279 | +0.24% | 0% | $7,292,946 |
| MILLENNIUM MANAGEMENT LLC | 0.8% | 371,373 | +28% | 0.01% | $7,275,197 |
| Bridge City Capital, LLC | 0.72% | 335,105 | +42% | 1.8% | $6,564,707 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 0.71% | 330,457 | +2.1% | 0.13% | $6,473,653 |
| GOLDMAN SACHS GROUP INC | 0.71% | 329,388 | -41% | 0% | $6,452,711 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
48
Latest
Q1 2026
Rows shown
1-25 of 48
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 32,342,484 | $633,964,637 | -$32,492,122 | $19.59 | 213 |
| 2025 Q4 | 33,557,786 | $898,637,402 | +$25,045,961 | $26.78 | 233 |
| 2025 Q3 | 32,747,166 | $872,750,705 | +$1,263,197 | $26.65 | 240 |
| 2025 Q2 | 32,731,709 | $751,532,890 | -$21,672,562 | $22.96 | 243 |
| 2025 Q1 | 33,249,489 | $963,158,808 | -$63,190,016 | $28.99 | 240 |
| 2024 Q4 | 35,163,514 | $1,305,816,189 | -$16,188,647 | $37.13 | 261 |
| 2024 Q3 | 35,330,537 | $1,713,563,419 | +$41,888,246 | $48.53 | 276 |
| 2024 Q2 | 34,395,410 | $1,376,025,520 | +$31,905,251 | $40.00 | 268 |
| 2024 Q1 | 33,566,615 | $1,473,434,135 | -$321,352 | $43.91 | 271 |
| 2023 Q4 | 33,295,380 | $2,059,042,180 | +$87,201,045 | $61.85 | 273 |
| 2023 Q3 | 32,003,084 | $1,472,015,140 | +$20,443,300 | $45.99 | 253 |
| 2023 Q2 | 31,353,069 | $1,801,848,806 | +$73,791,648 | $57.47 | 241 |
| 2023 Q1 | 30,206,509 | $1,132,914,126 | +$45,004,448 | $37.50 | 216 |
| 2022 Q4 | 29,163,019 | $817,271,726 | -$23,406,379 | $28.02 | 208 |
| 2022 Q3 | 29,873,966 | $840,021,516 | -$35,843,317 | $28.10 | 196 |
| 2022 Q2 | 30,557,166 | $1,062,910,134 | +$40,970,389 | $34.79 | 217 |
| 2022 Q1 | 29,830,020 | $1,070,980,758 | +$25,890,372 | $35.90 | 201 |
| 2021 Q4 | 29,169,816 | $678,795,680 | +$19,582,653 | $23.29 | 165 |
| 2021 Q3 | 27,926,297 | $530,762,683 | +$12,225,786 | $19.01 | 136 |
| 2021 Q2 | 27,261,956 | $549,556,724 | +$25,712,540 | $20.16 | 142 |
| 2021 Q1 | 26,031,138 | $476,843,577 | +$545,086 | $18.32 | 129 |
| 2020 Q4 | 25,994,308 | $522,683,040 | -$2,775,804 | $20.11 | 126 |
| 2020 Q3 | 26,220,579 | $491,828,114 | -$4,779,592 | $18.75 | 131 |
| 2020 Q2 | 26,338,746 | $591,056,212 | +$55,460,558 | $22.46 | 132 |
| 2020 Q1 | 23,920,591 | $355,117,215 | -$14,172,545 | $14.84 | 105 |