Director Richard Prins sells 7,973 Amphastar (AMPH) shares at $20.30

Q: How many Amphastar (AMPH) shares did Richard K. Prins sell and at what price?

Richard K. Prins sold 7,973 shares of Amphastar common stock at a price of $20.30 per share . The transaction was reported as a sale in open market or private transaction on 2026-08-11.

Q: What type of security did Richard K. Prins trade in the latest AMPH Form 4?

Richard K. Prins traded Common Stock of Amphastar Pharmaceuticals in the latest Form 4. He sold 7,973 shares at $20.30 per share , and now directly owns 29,625 shares after the transaction.

Filing Impact

(Moderate)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Amphastar Pharmaceuticals, Inc. director Richard K. Prins reported a sale of 7,973 shares of common stock on 2026-08-11 in a sale in open market or private transaction at $20.30 per share. Following this transaction, he directly holds 29,625 shares of Amphastar common stock.

Insider Trade Summary

Net Seller: 7,973 shares

Net Sell 1 txn

Insider PRINS RICHARD K

Role Director

Sold 7,973 shs ($162K)

Type	Security	Shares	Price	Value
Sale	Common Stock	7,973	$20.30	$162K

Holdings After Transaction: Common Stock — 29,625 shares (Direct)

Key Figures

Shares sold: 7,973 shares Sale price: $20.30 per share Shares owned after transaction: 29,625 shares

3 metrics

Shares sold 7,973 shares Common stock sale reported on 2026-08-11

Sale price $20.30 per share Price for the 7,973-share common stock sale

Shares owned after transaction 29,625 shares Direct common stock holdings following the sale

FAQ

What insider transaction did AMPH report for director Richard K. Prins?

Amphastar Pharmaceuticals (AMPH) reported that director Richard K. Prins sold 7,973 shares of common stock on 2026-08-11 at $20.30 per share in a sale classified as an open market or private transaction.

How many Amphastar (AMPH) shares did Richard K. Prins sell and at what price?

Richard K. Prins sold 7,973 shares of Amphastar common stock at a price of $20.30 per share. The transaction was reported as a sale in open market or private transaction on 2026-08-11.

How many Amphastar (AMPH) shares does Richard K. Prins hold after this sale?

After the 7,973-share sale, Richard K. Prins directly holds 29,625 shares of Amphastar Pharmaceuticals common stock. This post-transaction holding reflects his remaining direct ownership position reported in the Form 4 filing.

Was the August 11, 2026 AMPH insider trade by Richard K. Prins a purchase or sale?

The August 11, 2026 transaction reported by Richard K. Prins was a sale of Amphastar Pharmaceuticals common stock. It is coded as a sale in open market or private transaction under the Form 4 reporting rules.

What type of security did Richard K. Prins trade in the latest AMPH Form 4?

Richard K. Prins traded Common Stock of Amphastar Pharmaceuticals in the latest Form 4. He sold 7,973 shares at $20.30 per share, and now directly owns 29,625 shares after the transaction.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/12/2026 - 06:15 PM Accepted by SEC EDGAR 08/12/2026 - 06:14 PM

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^*

PRINS RICHARD K

(Last)

(First)

(Middle)

C/O AMPHASTAR PHARMACEUTICALS, INC.

11570 6TH STREET

(Street)

RANCHO CUCAMONGA

CALIFORNIA

91730

(City)

(State)

(Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/11/2026

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

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

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

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	08/11/2026		S		7,973	D	$20.3	29,625	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

	/s/ Eva Wen, by power of attorney	08/12/2026
	** 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.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR