Amphastar director granted RSUs and stock options

Amphastar Pharmaceuticals director David Russell Gaugh received new equity awards as part of his compensation.

Rhea-AI Filing Summary

Amphastar Pharmaceuticals director David Russell Gaugh received new equity awards as part of his compensation. He was granted 8,143 shares of Common Stock in the form of restricted stock units, which fully vest on June 1, 2027. Following this grant, he directly holds 14,447 Common Stock shares. He was also awarded stock options covering 17,365 shares of Common Stock at an exercise price of $18.42 per share. All of these options vest on June 1, 2027 and expire on June 1, 2036, giving him the right to buy shares at that fixed price if the company performs well over time.

Insider Trade Summary

Grant/Award: 25,508 shares

Grant/Award 2 txns

Insider Gaugh David Russell

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	17,365	$0.00	$0.00
Grant/Award	Common Stock	8,143	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 17,365 contracts (Direct); Common Stock — 14,447 shares (Direct)

Footnotes (2)

1. F1. The reported shares are represented by restricted stock units, or RSUs, all of which vest on June 1, 2027.
2. F2. All of the shares subject to the option vest on June 1, 2027.

Key Figures

RSU grant: 8,143 shares Common shares held: 14,447 shares Option grant size: 17,365 shares +3 more

6 metrics

RSU grant 8,143 shares Restricted stock units vesting on June 1, 2027

Common shares held 14,447 shares Direct holdings after RSU grant

Option grant size 17,365 shares Stock options awarded on June 1, 2026

Option exercise price $18.42/share Conversion or exercise price for stock options

Option expiration June 1, 2036 Expiration date of stock options

RSU vesting date June 1, 2027 All granted RSUs vest on this date

Key Terms

restricted stock units, Stock Option (right to buy), exercise price, vest

4 terms

restricted stock units financial

"The reported shares are represented by restricted stock units, or RSUs, all of which vest on June 1, 2027."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Stock Option (right to buy) financial

"Stock Option (right to buy) reported as a derivative security with underlying Common Stock."

exercise price financial

"conversion_or_exercise_price of 18.4200 per share for the stock option grant."

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

vest financial

"All of the shares subject to the option vest on June 1, 2027."

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did Amphastar (AMPH) director David Russell Gaugh report?

David Russell Gaugh reported awards of restricted stock units and stock options. He received 8,143 RSUs in Common Stock and options for 17,365 shares, both granted as compensation and scheduled to vest on June 1, 2027.

How many Amphastar (AMPH) shares does David Russell Gaugh hold after this Form 4?

After the reported equity grant, David Russell Gaugh directly holds 14,447 shares of Amphastar Common Stock. This figure reflects his position immediately following the 8,143-share restricted stock unit award reported as of June 1, 2026.

What are the terms of David Russell Gaugh’s new Amphastar (AMPH) stock options?

Gaugh received stock options for 17,365 shares of Common Stock at an exercise price of $18.42 per share. All of these options vest on June 1, 2027 and expire on June 1, 2036, defining their potential exercise window.

When do David Russell Gaugh’s restricted stock units in Amphastar (AMPH) vest?

All 8,143 restricted stock units granted to David Russell Gaugh vest on June 1, 2027. Once vested, these RSUs convert into shares of Common Stock, increasing his directly held equity in Amphastar if he remains eligible through that date.

Is David Russell Gaugh’s Amphastar (AMPH) Form 4 a market purchase or compensation grant?

The Form 4 reflects compensation-related acquisitions, not open-market trades. The filing labels both transactions under code A as grants or awards, covering 8,143 RSUs and options for 17,365 shares of Common Stock at a fixed exercise price.

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

Form 4 Insider Transactions: What Each Field Means →

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Accepted by SEC EDGAR 06/03/2026 - 08:31 PM EDT 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^*

Gaugh David Russell

(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)
06/01/2026

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/01/2026		A		8,143(1)	A	$0	14,447	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
Stock Option (right to buy)	$18.42	06/01/2026		A		17,365		(2)	06/01/2036	Common Stock	17,365	$0	17,365	D

Explanation of Responses:

1. The reported shares are represented by restricted stock units, or RSUs, all of which vest on June 1, 2027.

2. All of the shares subject to the option vest on June 1, 2027.

	/s/ Eva Wen, by power of attorney	06/03/2026
	** 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)