Security Snapshot

Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH) Institutional Ownership

CUSIP: 03209R103

13F Institutional Holders and Ownership History from Q2 2014 to Q1 2026

Latest Period

Q1 2026

Institutions Reporting

207

Shares (Excl. Options)

31,878,220

Price

$19.59

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Type / Class
Equity / Common Stock
Symbol
AMPH on Nasdaq
Shares outstanding
46,377,939
Price per share
$21.63
All holders as of 31 Mar 2026
Q1 2026
Total 13F shares
31,878,220
Total reported value
$624,842,838
% of total 13F portfolios
0%
Share change
-1,421,537
Value change
-$38,656,581
Number of holders
207
Price from insider filings
$21.63
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors

Quick Takeaways

  • AMPH - Amphastar Pharmaceuticals, Inc. - Common Stock is tracked under CUSIP 03209R103.
  • 207 institutions reported positions in Q1 2026.
  • 2 significant owners is listed from Schedule 13D/13G reporting.

What Changed

  • Holder count moved from 232 to 207 between Q4 2025 and Q1 2026.
  • Reported value moved from $898,632,046 to $624,842,838.

Why This Matters

  • 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.

Source Evidence

Source: SEC Form 13F

Latest holder context comes from 207 institutions filings for Q1 2026.

Open SEC Evidence

Investment Quick Answers

What is CUSIP 03209R103?
CUSIP 03209R103 identifies AMPH - Amphastar Pharmaceuticals, Inc. - Common Stock in SEC 13F datasets.

Where can I see the latest institutional holders?
Review the Q1 2026 holders report and the ownership history table below.

Significant Owners of Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH) based on Schedule 13D/G filings

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, 207 institutional investors reported holding 31,878,220 shares of Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH). This represents 69% of the company’s total 46,377,939 outstanding shares.

Top 25 Institutional Shareholders

The largest institutional shareholders of Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH) together control 54% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.

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

Institutional Holders of Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH) across Reporting Periods

Period Reported Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2026 Q1 31,878,220 $624,842,838 -$38,656,581 $19.59 207
2025 Q4 33,557,586 $898,632,046 +$25,047,300 $26.78 232
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
2019 Q4 24,555,993 $473,689,883 +$9,587,777 $19.29 116
2019 Q3 24,085,264 $477,743,008 +$39,111,793 $19.83 130
2019 Q2 22,325,317 $471,212,995 +$11,702,564 $21.11 129
2019 Q1 22,418,206 $457,984,013 +$3,993,993 $20.43 133
2018 Q4 22,224,435 $442,228,625 +$31,389,222 $19.90 129
2018 Q3 20,634,989 $396,966,940 +$11,955,958 $19.24 104
2018 Q2 20,104,298 $306,846,558 -$10,112,452 $15.26 110
2018 Q1 20,667,512 $387,520,854 +$4,863,050 $18.75 114
2017 Q4 20,638,746 $396,981,826 +$6,676,577 $19.24 104
2017 Q3 20,292,672 $362,569,441 -$2,721,250 $17.87 100
2017 Q2 20,446,108 $365,150,134 +$4,539,252 $17.86 106
2017 Q1 20,427,180 $296,235,043 +$42,154,775 $14.50 114
2016 Q4 22,346,694 $411,905,913 +$7,350,529 $18.42 135
2016 Q3 22,197,017 $421,063,192 +$114,569,375 $18.97 134
2016 Q2 16,184,121 $261,086,844 +$32,114,465 $16.12 104
2016 Q1 14,259,461 $171,232,000 -$8,847,105 $12.00 93
2015 Q4 14,731,020 $209,636,387 +$12,973,432 $14.23 93
2015 Q3 13,587,192 $158,819,188 -$3,114,129 $11.69 91
2015 Q2 13,322,195 $234,151,768 +$48,772,625 $17.58 85
2015 Q1 10,590,488 $158,146,254 +$40,390,095 $14.96 57
2014 Q4 7,933,683 $92,124,442 +$5,403,296 $11.61 54
2014 Q3 7,242,472 $84,362,000 +$80,866,904 $11.64 44
2014 Q2 300,000 $3,003,000 +$3,003,000 $10.01 2
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