Company · Ownership research

Amphastar Pharmaceuticals, Inc. AMPH

CIK 0001297184 · CUSIP 03209R103

Insider trading Initial holdings Institutional holders

Quarter-end disclosures, not live holdings.

Several CUSIPs are reported for this company; this page shows CUSIP 03209R103 (AMPH), not CUSIP 03209R903 (AMPH), CUSIP 03209R953 (AMPH), and does not merge CUSIPs.

This page lists the top 20 of 279 rows by value; the complete set is available through the API.

Some filings reported values in thousands; those figures were scaled ×1,000 to dollars.

Top 20 institutions

Weight means this stock's share of the manager's own portfolio.

By reported value

#	Manager	Value	Manager weight	Change vs prior	Source
01	BlackRock, Inc. CIK 2012383 · View history	$292.77M 6,032,722 shares	0.01%	—	SEC filing ↗ Nov 13, 2024	▾
02	VANGUARD GROUP INC CIK 102909 · View history	$131.59M 2,711,473 shares	0.00%	+38.61K(+1.40%)Added	SEC filing ↗ Nov 13, 2024	▾
03	TD Asset Management Inc CIK 1056053 · View history	$102.52M 2,135,038 shares	0.09%	+443.47K(+26.20%)Added	SEC filing ↗ Nov 1, 2024	▾
04	FEDERATED HERMES, INC. CIK 1056288 · View history	$94.49M 1,947,100 shares	0.21%	+2.30K(+0.10%)Added	SEC filing ↗ Nov 13, 2024	▾
05	NEUBERGER BERMAN GROUP LLC CIK 1465109 · View history	$78.38M 1,615,088 shares	0.06%	-7.52K(-0.50%)Reduced	SEC filing ↗ Nov 14, 2024	▾
06	STATE STREET CORP CIK 93751 · View history	$74.27M 1,530,464 shares	0.00%	+928(+0.10%)Added	SEC filing ↗ Nov 14, 2024	▾
07	FULLER & THALER ASSET MANAGEMENT, INC. CIK 1082327 · View history	$61.19M 1,260,767 shares	0.24%	-12.05K(-0.90%)Reduced	SEC filing ↗ Nov 13, 2024	▾
08	Epoch Investment Partners, Inc. CIK 1305841 · View history	$57.80M 1,191,110 shares	0.26%	+112.26K(+10.40%)Added	SEC filing ↗ Nov 13, 2024	▾
09	DIMENSIONAL FUND ADVISORS LP CIK 354204 · View history	$53.06M 1,093,302 shares	0.01%	+23.03K(+2.20%)Added	SEC filing ↗ Nov 7, 2024	▾
10	GEODE CAPITAL MANAGEMENT, LLC CIK 1214717 · View history	$44.67M 920,363 shares	0.00%	+14.02K(+1.50%)Added	SEC filing ↗ Nov 12, 2024	▾
11	MORGAN STANLEY CIK 895421 · Amended · View history	$32.89M 677,626 shares	0.00%	+67.49K(+11.10%)Added	SEC filing ↗ May 14, 2025	▾
12	AMERICAN CENTURY COMPANIES INC CIK 748054 · View history	$31.04M 639,592 shares	0.02%	-100.82K(-13.60%)Reduced	SEC filing ↗ Nov 12, 2024	▾
13	NORTHERN TRUST CORP CIK 73124 · View history	$28.31M 583,362 shares	0.00%	+19.24K(+3.40%)Added	SEC filing ↗ Nov 13, 2024	▾
14	PRICE T ROWE ASSOCIATES INC /MD/ CIK 80255 · View history	$27.61M 568,894 shares	0.00%	-15.01K(-2.60%)Reduced	SEC filing ↗ Nov 14, 2024	▾
15	MARSHALL WACE, LLP CIK 1318757 · View history	$27.59M 568,494 shares	0.04%	+341.37K(+150.30%)Added	SEC filing ↗ Nov 14, 2024	▾
16	Boston Trust Walden Corp CIK 1534866 · View history	$26.19M 539,639 shares	0.18%	+539.64KNew	SEC filing ↗ Oct 24, 2024	▾
17	RENAISSANCE TECHNOLOGIES LLC CIK 1037389 · View history	$23.75M 489,400 shares	0.04%	-48.30K(-9.00%)Reduced	SEC filing ↗ Nov 13, 2024	▾
18	BESSEMER GROUP INC CIK 1054074 · View history	$23.15M 477,021 shares	0.04%	+10.79K(+2.30%)Added	SEC filing ↗ Nov 12, 2024	▾
19	GOLDMAN SACHS GROUP INC CIK 886982 · View history	$21.81M 449,389 shares	0.00%	+295.78K(+192.60%)Added	SEC filing ↗ Nov 14, 2024	▾
20	Mesirow Institutional Investment Management, Inc. CIK 1947591 · View history	$20.09M 413,949 shares	1.53%	+60.50K(+17.10%)Added	SEC filing ↗ Nov 13, 2024	▾

Showing 20 / 279 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions

279

Cancelled or null records excluded

Disclosed shares

35,434,450

Not deduplicated across managers

Disclosed value

$1.72B

Not market cap or free float

Reporting institutions by quarter

Counts also change with data coverage and reporting entities; they do not measure net buying. Distinct managers with a live stock row in this CUSIP; totals may include overlapping filings and are not a share of the company.

Amphastar Pharmaceuticals, Inc. · Q3 2024

Explore all 279 reporting institutions.

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Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.