[Form 4] Amphastar Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Amphastar Pharmaceuticals (AMPH) – SEC Form 4

Director Floyd F. Petersen disclosed the sale of 500 common shares on 01 Aug 2025 at a weighted-average price of $20.8315. The transaction was executed under a Rule 10b5-1 trading plan adopted 26 Nov 2024, indicating it was pre-scheduled rather than discretionary. After the sale, Petersen directly owns 77,031 shares, so the disposition equals roughly 0.6 % of his stake and is immaterial relative to Amphastar’s total share count. No derivative securities activity or additional insider trades were reported.

The filing therefore conveys routine insider diversification without signaling a change in corporate fundamentals or outlook.

Insights

Equity Research Analyst

TL;DR: Minor, pre-planned insider sale; no valuation impact expected.

The $10 k transaction (<500 × $20.83>) represents less than 1 % of Petersen’s holdings and an immaterial fraction of AMPH’s float. Execution under Rule 10b5-1 limits information-content risk. With no concurrent business updates, the sale should not influence earnings expectations or multiple expansion. I rate the market impact as neutral.

Corporate Governance Specialist

TL;DR: Filing is procedurally sound; no governance concerns.

The director filed within the two-business-day window, used a 10b5-1 plan, and retained a sizeable ownership position, aligning interests with shareholders. No red flags such as large undisclosed derivatives or clustered insider selling are present. Governance risk remains unchanged.

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).

X

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^*

Petersen Floyd F.

(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
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
08/01/2025

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	08/01/2025		S(1)		500	D	$20.8315(2)	77,031	D

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

Explanation of Responses:

1. The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 26, 2024.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.485 to $21.105, 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.

	/s/ Eva Wen, by power of attorney	08/04/2025
	** 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).
** 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.

FAQ

How many AMPH shares did Director Floyd F. Petersen sell on August 1, 2025?

He sold 500 shares of Amphastar Pharmaceuticals common stock.

What was the average sale price of the AMPH shares?

The weighted-average price reported was $20.8315 per share.

How many AMPH shares does Petersen still own after the transaction?

He beneficially owns 77,031 shares following the sale.

Was the insider sale conducted under a Rule 10b5-1 trading plan?

Yes. The plan was adopted on November 26, 2024 and governed this transaction.

Did the Form 4 disclose any derivative securities activity?

No derivative securities were acquired or disposed of in this filing.