Yakob Liawatidewi - 09 Mar 2026 Form 4 Insider Report for Amphastar Pharmaceuticals, Inc. (AMPH)

Role: EVP CORP ADMIN CENTER, Director
Signature: /s/ Eva Wen, by power of attorney
Issuer symbol: AMPH
Transactions as of: 09 Mar 2026
Net transactions value: $0
Form type: 4
Filing time: 11 Mar 2026, 18:26:27 UTC
Previous filing: 10 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Liawatidewi Yakob	EVP CORP ADMIN CENTER, Director	C/O AMPHASTAR PHARMACEUTICALS, INC., 11570 6TH STREET, RANCHO CUCAMONGA	/s/ Eva Wen, by power of attorney	11 Mar 2026	0001743927

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	AMPH	Common Stock	Award		+35,450	+40%	$0.000000^*	124,795	09 Mar 2026	Direct	F1
transaction	AMPH	Common Stock	Tax liability		-1,870	-1.5%	$18.91^*	122,925	10 Mar 2026	Direct	F2
holding	AMPH	Common Stock						2,459	09 Mar 2026	See footnote	F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	AMPH	Employee Stock Option (right to buy)	Award		+73,126		$0.000000^*	73,126	09 Mar 2026	Common Stock	73,126	$19.21	Direct	F4

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The reported shares are represented by restricted stock units, or RSUs, which vest in four equal annual installments beginning on March 9, 2027.
F2	The reported shares were withheld to satisfy the reporting person's tax liability in connection with the vesting of RSUs.
F3	The reported shares are held of record by the Yakob and Sunmoon Trust dated July 25, 2013 for which the reporting person serves as a trustee.
F4	The shares subject to the option vest in four equal annual installments beginning on March 9, 2027.