AMPHASTAR PHARMACEUTICALS IN

Ticker: AMPH CUSIP: 03209R103 Class: Common Stock

ARROWSTREET CAPITAL, LIMITED PARTNERSHIP's Holding History (CIK: 0001164508)

Note: Option positions (PUT/CALL) are excluded.

Q4 2025

Shares 559,426 Value ($000) $14,981 Avg Close $25.76 Range $22.94 - $29.00

Q3 2025

Shares 392,310 Value ($000) $10,455 Avg Close $25.82 Range $20.39 - $31.26

Q2 2025

Shares 81,239 Value ($000) $1,865 Avg Close $24.82 Range $22.64 - $29.27

Q1 2024

Shares 22,539 Value ($000) $1 Avg Close $51.65 Range $42.16 - $65.92

Q3 2023

Shares 28,230 Value ($000) $1 Avg Close $54.55 Range $44.86 - $67.66

Q2 2023

Shares 29,099 Value ($000) $2 Avg Close $44.33 Range $35.62 - $58.70

Q1 2023

Shares 74,274 Value ($000) $3 Avg Close $32.78 Range $27.58 - $38.22

Q4 2022

Shares 166,040 Value ($000) $5 Avg Close $29.04 Range $26.76 - $31.64

Q3 2022

Shares 201,065 Value ($000) $5,650 Avg Close $32.65 Range $27.10 - $39.07

Q2 2022

Shares 304,672 Value ($000) $10,600 Avg Close $35.69 Range $28.64 - $44.46

Q1 2022

Shares 391,585 Value ($000) $14,058 Avg Close $28.36 Range $22.07 - $37.16

Q4 2021

Shares 416,049 Value ($000) $9,690 Avg Close $20.45 Range $18.12 - $23.85

Q3 2021

Shares 198,472 Value ($000) $3,773 Avg Close $19.59 Range $17.56 - $21.63

Q2 2021

Shares 145,918 Value ($000) $2,942 Avg Close $18.84 Range $16.91 - $20.94

Q1 2021

Shares 55,869 Value ($000) $1,024 Avg Close $18.59 Range $17.11 - $20.93

Q4 2019

Shares 520,984 Value ($000) $10,050 Avg Close $19.18 Range $16.71 - $20.89

Q3 2019

Shares 453,835 Value ($000) $9,000 Avg Close $20.83 Range $18.66 - $22.85

Q2 2019

Shares 166,302 Value ($000) $3,511 Avg Close $20.90 Range $18.60 - $23.06

Q1 2019

Shares 150,541 Value ($000) $3,076 Avg Close $22.40 Range $19.32 - $25.43

Q2 2018

Shares 34,840 Value ($000) $532 Avg Close $17.48 Range $14.40 - $19.94

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	559,426	$14,981	$25.76	$22.94 - $29.00
Q3 2025	392,310	$10,455	$25.82	$20.39 - $31.26
Q2 2025	81,239	$1,865	$24.82	$22.64 - $29.27
Q1 2024	22,539	$1	$51.65	$42.16 - $65.92
Q3 2023	28,230	$1	$54.55	$44.86 - $67.66
Q2 2023	29,099	$2	$44.33	$35.62 - $58.70
Q1 2023	74,274	$3	$32.78	$27.58 - $38.22
Q4 2022	166,040	$5	$29.04	$26.76 - $31.64
Q3 2022	201,065	$5,650	$32.65	$27.10 - $39.07
Q2 2022	304,672	$10,600	$35.69	$28.64 - $44.46
Q1 2022	391,585	$14,058	$28.36	$22.07 - $37.16
Q4 2021	416,049	$9,690	$20.45	$18.12 - $23.85
Q3 2021	198,472	$3,773	$19.59	$17.56 - $21.63
Q2 2021	145,918	$2,942	$18.84	$16.91 - $20.94
Q1 2021	55,869	$1,024	$18.59	$17.11 - $20.93
Q4 2019	520,984	$10,050	$19.18	$16.71 - $20.89
Q3 2019	453,835	$9,000	$20.83	$18.66 - $22.85
Q2 2019	166,302	$3,511	$20.90	$18.60 - $23.06
Q1 2019	150,541	$3,076	$22.40	$19.32 - $25.43
Q2 2018	34,840	$532	$17.48	$14.40 - $19.94