Security Snapshot

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

CUSIP: 03209R103

13F Institutional Holders and Ownership History from Q2 2014 to Q3 2026

13F reference period

Q2 2026

Institutions Reporting

209

Shares (Excl. Options)

28.32MFull value: 28,318,139 · shares · 30 Jun 2026

Price

$20.18

The headline uses the Q2 2026 reference period after its reporting deadline. Available reports may still be incomplete or amended. Newer periods in the history table contain incoming reports and may be incomplete.

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Latest holder snapshot 5 signals
Portfolio coverage rank
0%
Share change
-3,928,384
Value change
-$76,994,315
Number of holders
209
Security identity Names, identifiers, and filing context for this profile. 1 source field
Underlying class
Common Stock
Issuer context Names, identifiers, and filing context for this profile. 3 identity fields
Shares outstanding
44,328,981
SEC-reported price per share
$25.81
Insider filing price
$25.81
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Filing notes and source

Key facts

  • AMPH - Amphastar Pharmaceuticals, Inc. - Common Stock is tracked under CUSIP 03209R103.
  • 209 institutions reported positions in Q2 2026.
  • 3 significant owners is listed from Schedule 13D/13G reporting.

Change

  • Holder count moved from 214 to 209 between Q1 2026 and Q2 2026.
  • SEC-reported value moved from
    $634.05MFull value: $634,049,603 · USD · 31 Mar 2026
    to
    $571.46MFull value: $571,459,831 · USD · 30 Jun 2026
    .

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

Latest holder context comes from 209 institutions filings for Q2 2026.

Open SEC evidence

Security key

03209R103

13F reference period

Q2 2026

13F holders

209

13D/G owners

3

CIK / CUSIP context first

13D/G owners

Significant owners

Large-stake holder rows connected to Schedule 13D/G evidence.

Rows
3
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
DIMENSIONAL FUND ADVISORS LP 5.2% $46,517,059 2,305,107 Dimensional Fund Advisors LP 30 Jun 2026
As of 30 Jun 2026, 209 institutional investors reported holding
28.32MFull value: 28,318,139 · shares · 30 Jun 2026
shares of Amphastar Pharmaceuticals, Inc. - Common Stock (AMPH). This represents 64% of the company’s total
44.33MFull value: 44,328,981 · shares · Stored outstanding share count
outstanding shares.

13F concentration

Top 25 institutional shareholders

Largest 13F positions for this security by reported shares and value.

Top holder share
50%
Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
BlackRock, Inc. 12% 5,224,934 -3.6% 0% $105,439,168
DIMENSIONAL FUND ADVISORS LP 5.2% 2,305,107 +14% 0.01% $46,519,189
STATE STREET CORP 3.7% 1,642,126 +2.2% 0% $33,138,103
VANGUARD CAPITAL MANAGEMENT LLC 3.3% 1,481,952 -4% 0% $29,905,791
AMERICAN CENTURY COMPANIES INC 2.7% 1,176,626 +16% 0.01% $23,744,313
MARSHALL WACE, LLP 2.4% 1,066,322 +4% 0.02% $21,518,378
GEODE CAPITAL MANAGEMENT, LLC 2.2% 969,840 -0.7% 0% $19,575,036
FULLER & THALER ASSET MANAGEMENT, INC. 2.1% 949,238 -32% 0.05% $19,155,615
D. E. Shaw & Co., Inc. 2% 887,048 +33% 0.01% $17,900,629
VANGUARD PORTFOLIO MANAGEMENT LLC 1.8% 809,568 +2.8% 0% $16,337,082
LSV ASSET MANAGEMENT 1.4% 642,014 -1.5% 0.02% $12,956,000
RENAISSANCE TECHNOLOGIES LLC 1.2% 525,100 -5.2% 0.01% $10,596,518
GOLDMAN SACHS GROUP INC 1.1% 505,360 +53% 0% $10,198,165
SYSTEMATIC FINANCIAL MANAGEMENT LP 0.99% 437,384 -3.4% 0.18% $8,826,439
MORGAN STANLEY 0.98% 434,840 +3.5% 0% $8,775,081
UBS Group AG 0.89% 393,110 -6.5% 0% $7,932,960
HRT FINANCIAL LP 0.87% 387,530 +590% 0.01% $7,820,000
DENALI ADVISORS LLC 0.85% 375,965 +41% 0.76% $7,586,974
NORTHERN TRUST CORP 0.84% 370,991 -0.35% 0% $7,486,598
Bridge City Capital, LLC 0.76% 338,708 +1.1% 1.6% $6,835,127
CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.7% 310,178 -3.4% 0% $6,259,392
BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.67% 298,954 -9.5% 0.11% $6,032,892
ROYCE & ASSOCIATES LP 0.66% 294,758 -27% 0.05% $5,948,216
TWO SIGMA INVESTMENTS, LP 0.56% 248,115 +80% 0% $5,006,961
FIRST TRUST ADVISORS LP 0.56% 246,951 +64% 0% $4,983,471

Quarter history

Institutional holders across reporting periods

Holder count, reported shares/value, and median price by quarter.

Periods
50
Headline period
Q2 2026
Rows shown
1-25 of 50
Period 13F Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2026 Q3 441,467 $11,400,414 -$1,267,743 $25.81 43
2026 Q2 28,318,139 $571,459,831 -$76,994,315 $20.18 209
2026 Q1 32,346,840 $634,049,603 -$32,823,433 $19.59 214
2025 Q4 33,562,174 $898,754,913 +$25,045,961 $26.78 234
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
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