PDT Partners’s Amphastar Pharmaceuticals AMPH Stock Holding History

PDT Partners’s Portfolio AMPH Stock Details AMPH Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q1	$224K	Buy	+11,441	New	+$280K	0.01%	488
2025 Q4	–	Sell	-14,630	Closed	-$390K	–	553
2025 Q3	$390K	Hold	14,630	–	–	0.02%	477
2025 Q2	$336K	Buy	+14,630	New	+$363K	0.02%	582
2025 Q1	–	Sell	-90,484	Closed	-$3.36M	–	737
2024 Q4	$3.36M	Buy	90,484 +9,300	+11%	+$425K	0.3%	109
2024 Q3	$3.94M	Buy	81,184 +71,482	+737%	+$3.14M	0.35%	63
2024 Q2	$388K	Buy	+9,702	New	+$402K	0.04%	518
2022 Q3	–	Sell	-54,804	Closed	-$1.91M	–	830
2022 Q2	$1.91M	Buy	54,804 +20,415	+59%	+$729K	0.17%	184
2022 Q1	$1.24M	Buy	34,389 +930	+3%	+$26.4K	0.11%	307
2021 Q4	$779K	Buy	33,459 +5,922	+22%	+$121K	0.06%	426
2021 Q3	$523K	Buy	+27,537	New	+$539K	0.04%	468
2015 Q3	–	Sell	-20,650	Closed	-$363K	–	1248
2015 Q2	$363K	Buy	+20,650	New	+$322K	0.01%	1075

Other funds holding AMPH

BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

Dimensional Fund Advisors Austin, Texas $481B AUM 30.42% 1-Year Est. Return

State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return

VCM

Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM

TD Asset Management Toronto, Ontario, Canada $123B AUM 34.51% 1-Year Est. Return

Fuller & Thaler Asset Management San Mateo, California $29.7B AUM 43.33% 1-Year Est. Return

Marshall Wace London, United Kingdom $100B AUM 35.1% 1-Year Est. Return

American Century Companies Kansas City, Missouri $194B AUM 35% 1-Year Est. Return

Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return

BTW

Boston Trust Walden Boston, Massachusetts $13.1B AUM 24.63% 1-Year Est. Return

PDT Partners's AMPH Position: Q1 2026 in Review

PDT Partners opened a new position in Amphastar Pharmaceuticals (AMPH) in Q1 2026: 11,441 shares worth $224K. The stake represents 0.01% of the portfolio and ranks #488 among its holdings. This is a return to the name: PDT Partners previously reported a position in AMPH as recently as Q3 2025.

PDT Partners first reported a position in AMPH in Q2 2015 and has held it in 11 quarters since. The position peaked at $3.94M in Q3 2024. 215 funds tracked by Wall St. Rank hold AMPH as of Q1 2026.

PDT Partners held 11,441 shares of Amphastar Pharmaceuticals worth $224K as of Q1 2026.
Amphastar Pharmaceuticals was a new PDT Partners position in Q1 2026.
Amphastar Pharmaceuticals made up 0.01% of PDT Partners's portfolio in Q1 2026, its #488 holding.
PDT Partners first reported a position in Amphastar Pharmaceuticals in Q2 2015 and has held it in 11 quarters since.
PDT Partners's Amphastar Pharmaceuticals position peaked at $3.94M in Q3 2024.
215 funds tracked by Wall St. Rank held Amphastar Pharmaceuticals as of Q1 2026.

Based on PDT Partners's 13F filing for Q1 2026, filed 15 May 2026.