Amphastar Pharmaceuticals (AMPH) executive logs option exercise and 9,787-share sale

Rhea-AI Filing Summary

Amphastar Pharmaceuticals' senior executive reports option exercise and share sale. The Senior EVP, Production Center exercised an employee stock option to acquire 9,787 shares of Amphastar Pharmaceuticals common stock at an exercise price of $11.33 per share on 12/17/2025. On the same day, 9,787 common shares were sold at a weighted average price of $26.1959 per share, with individual sale prices ranging from $25.97 to $26.50.

After these transactions, the reporting person directly owns 138,043 common shares. In addition, 99,668 shares are held by the Zhou Family Trust, for which the reporting person serves as trustee, and 5,000 shares are held by the reporting person’s spouse. The option shares were fully vested and immediately exercisable at the time of exercise.

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

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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^*

Zhou Rong

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SENIOR EVP, PRODUCTION CENTER

3. Date of Earliest Transaction (Month/Day/Year)
12/17/2025

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	12/17/2025		M		9,787	A	$11.33	147,830(1)	D
Common Stock	12/17/2025		S		9,787	D	$26.1959(2)	138,043	D
Common Stock								99,668	I	See footnote(3)
Common Stock								5,000	I	See footnote(4)

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)	$11.33	12/17/2025		M			9,787	(5)	03/17/2026	Common Stock	9,787	$0	0	D

Explanation of Responses:

1. Includes 545 shares acquired on May 31, 2025 and one share acquired on November 30, 2025 under the Issuer's 2014 Employee Stock Purchase Plan.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.97 to $26.50, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

3. The shares are held of record by the Zhou Family Trust for which the reporting person serves as a trustee.

4. The shares are held of record by the reporting person's spouse.

5. Shares subject to the option are fully vested and immediately exercisable.

	/s/ Eva Wen, by power of attorney	12/18/2025
	** 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).
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FAQ

What insider transaction did AMPH's executive report on 12/17/2025?

The Senior EVP, Production Center of Amphastar Pharmaceuticals, Inc. (AMPH) exercised an employee stock option for 9,787 shares at $11.33 per share and sold 9,787 common shares on 12/17/2025.

At what prices were the Amphastar (AMPH) shares sold in this insider trade?

The reported sale of 9,787 Amphastar common shares had a weighted average price of $26.1959 per share, with individual trades executed at prices ranging from $25.97 to $26.50.

How many Amphastar (AMPH) shares does the reporting person own after the transaction?

Following the reported transactions, the executive directly owns 138,043 Amphastar common shares, with an additional 99,668 shares held by the Zhou Family Trust and 5,000 shares held by the executive’s spouse.

What type of derivative security was exercised in this Amphastar (AMPH) insider filing?

The reporting person exercised an employee stock option (right to buy) with an exercise price of $11.33, covering 9,787 shares of Amphastar common stock. The option shares were fully vested and immediately exercisable.

Were the Amphastar (AMPH) shares sold in multiple transactions?

Yes. The filing states that the 9,787 shares sold were executed in multiple transactions at prices ranging from $25.97 to $26.50, and the reported price is a weighted average.

How are some of the Amphastar (AMPH) shares held indirectly by the reporting person?

99,668 shares are held of record by the Zhou Family Trust, for which the reporting person serves as trustee, and 5,000 shares are held of record by the reporting person’s spouse.