Amphastar EVP granted RSUs and stock options

Rhea-AI Filing Summary

Amphastar Pharmaceuticals EVP Liawatidewi Yakob reported routine equity compensation and related tax withholding. She received 35,450 shares of Common Stock in the form of restricted stock units that vest in four equal annual installments beginning on March 9, 2027. She was also granted employee stock options for 73,126 shares of Common Stock at an exercise price of $19.21 per share, vesting in four equal annual installments starting on March 9, 2027 and expiring in 2036. In connection with RSU vesting, 1,870 shares of Common Stock were withheld to satisfy tax liabilities, a non‑market disposition. Following these events, she holds 122,925 Common Stock shares directly, 2,459 shares indirectly through the Yakob and Sunmoon Trust, and the newly granted 73,126 stock options.

Insider Trade Summary

Net Buyer: 33,580 shares

Net Buy 4 txns

Insider Liawatidewi Yakob

Role EVP CORP ADMIN CENTER

Type	Security	Shares	Price	Value
Exercise Price or Tax Liability	Common Stock	1,870	$18.91	$35K
Grant/Award	Employee Stock Option (right to buy)	73,126	$0.00	$0.00
Grant/Award	Common Stock	35,450	$0.00	$0.00
holding	Common Stock	--	--	--

Holdings After Transaction: Employee Stock Option (right to buy) — 73,126 shares (Direct); Common Stock — 122,925 shares (Direct); Common Stock — 2,459 shares (Indirect, See footnote)

Footnotes (4)

1. F1. The reported shares are represented by restricted stock units, or RSUs, which vest in four equal annual installments beginning on March 9, 2027.
2. F2. The reported shares were withheld to satisfy the reporting person's tax liability in connection with the vesting of RSUs.
3. 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.
4. F4. The shares subject to the option vest in four equal annual installments beginning on March 9, 2027.

FAQ

What did Amphastar (AMPH) EVP Liawatidewi Yakob report on this Form 4?

She reported routine equity compensation and tax withholding. Yakob received new restricted stock units and stock options, while shares were withheld to cover taxes on RSU vesting, with no open‑market buying or selling disclosed in this filing.

How many RSUs did Amphastar EVP Yakob receive according to the Form 4?

Yakob received 35,450 shares of Common Stock in the form of restricted stock units. These RSUs vest in four equal annual installments beginning on March 9, 2027, providing time-based equity compensation linked to her continued service with Amphastar Pharmaceuticals.

What stock options were granted to Amphastar (AMPH) EVP Liawatidewi Yakob?

She was granted employee stock options covering 73,126 shares of Common Stock at an exercise price of $19.21 per share. The options vest in four equal annual installments starting March 9, 2027 and expire in 2036, aligning long-term incentives with future company performance.

Why were 1,870 Amphastar shares disposed of in this Form 4 filing?

The 1,870 Common Stock shares were withheld to satisfy Yakob’s tax liability related to RSU vesting. This is recorded as a tax-withholding disposition, not an open‑market sale, and reflects standard treatment for equity compensation taxes rather than discretionary trading.

What are Liawatidewi Yakob’s Amphastar holdings after these transactions?

After the reported transactions, Yakob holds 122,925 shares of Common Stock directly and 2,459 shares indirectly through the Yakob and Sunmoon Trust. She also holds 73,126 newly granted employee stock options, which begin vesting on March 9, 2027 in four annual installments.

How do the reported transactions affect Amphastar (AMPH) insider ownership?

The filing shows an increase in Yakob’s equity-based compensation through RSUs and options, while shares withheld for taxes slightly reduced her direct stock count. Overall, the activity reflects standard executive compensation practices rather than strategic buying or selling decisions.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 03/11/2026 - 06:26 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Liawatidewi Yakob

(Last) (First) (Middle)

C/O AMPHASTAR PHARMACEUTICALS, INC.

11570 6TH STREET

(Street)

RANCHO CUCAMONGA CA 91730

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Amphastar Pharmaceuticals, Inc. [ AMPH ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP CORP ADMIN CENTER

3. Date of Earliest Transaction (Month/Day/Year)
03/09/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/09/2026		A		35,450(1)	A	$0	124,795	D
Common Stock	03/10/2026		F		1,870(2)	D	$18.91	122,925	D
Common Stock								2,459	I	See footnote(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	$19.21	03/09/2026		A		73,126		(4)	03/09/2036	Common Stock	73,126	$0	73,126	D

Explanation of Responses:

1. The reported shares are represented by restricted stock units, or RSUs, which vest in four equal annual installments beginning on March 9, 2027.

2. The reported shares were withheld to satisfy the reporting person's tax liability in connection with the vesting of RSUs.

3. 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.

4. The shares subject to the option vest in four equal annual installments beginning on March 9, 2027.

	/s/ Eva Wen, by power of attorney	03/11/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.