Jane Street’s Amphastar Pharmaceuticals AMPH Stock Holding History

Jane Street’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	$1.19M	Buy	61,000 +47,800	+362%	+$1.17M	﹤0.01%	6132
2025 Q4	$353K	Sell	13,200 -45,100	-77%	-$1.16M	﹤0.01%	8464
2025 Q3	$1.55M	Buy	+58,300	New	+$1.51M	﹤0.01%	5408
2024 Q4	–	Sell	-17,300	Closed	-$840K	–	9317
2024 Q3	$840K	Buy	17,300 +12,000	+226%	+$527K	﹤0.01%	6222
2024 Q2	$212K	Sell	5,300 -3,400	-39%	-$141K	﹤0.01%	8300
2024 Q1	$382K	Buy	+8,700	New	+$449K	﹤0.01%	7157
2022 Q4	–	Sell	-8,800	Closed	-$247K	–	9069
2022 Q3	$247K	Sell	8,800 -5,200	-37%	-$170K	﹤0.01%	7858
2022 Q2	$487K	Buy	+14,000	New	+$500K	﹤0.01%	6790

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 $12.2B AUM 12.45% 1-Year Est. Return

Jane Street's AMPH Position: Q1 2026 in Review

Jane Street reduced its Amphastar Pharmaceuticals (AMPH) stake by 57% in Q1 2026, selling an estimated $3.06M and leaving 92,475 shares worth $1.81M. The position accounts for ﹤0.01% of the portfolio, ranked #5289.

Jane Street first reported a position in AMPH in Q4 2021 and has held it in 18 quarters since. The position peaked at $5.83M in Q4 2025. 215 funds tracked by Wall St. Rank hold AMPH as of Q1 2026.

Jane Street held 92,475 shares of Amphastar Pharmaceuticals worth $1.81M as of Q1 2026.
Jane Street sold 125,062 Amphastar Pharmaceuticals shares in Q1 2026, an estimated $3.06M.
Amphastar Pharmaceuticals made up ﹤0.01% of Jane Street's portfolio in Q1 2026, its #5289 holding.
Jane Street first reported a position in Amphastar Pharmaceuticals in Q4 2021 and has held it in 18 quarters since.
Jane Street's Amphastar Pharmaceuticals position peaked at $5.83M in Q4 2025.
215 funds tracked by Wall St. Rank held Amphastar Pharmaceuticals as of Q1 2026.

Based on Jane Street's 13F filing for Q1 2026, filed 12 May 2026.