Amphastar VP plans sale of 10,000 shares

Amphastar Pharmaceuticals, Inc. (AMPH) is the issuer for a planned resale of its common stock under Rule 144 by Rong Zhou, identified as Vice President.

Rhea-AI Filing Summary

Amphastar Pharmaceuticals, Inc. (AMPH) is the issuer for a planned resale of its common stock under Rule 144 by Rong Zhou, identified as Vice President. The notice covers several blocks of common stock, including 10,000 shares acquired via an option exercise dated 09/01/2026 and additional smaller lots acquired through the company’s Employee Stock Purchase Plan on various dates from 2021 to 2023.

Key Figures

Largest common stock block to be sold: 10,000 shares ESPP acquisition 05/31/2021: 1,010 shares ESPP acquisition 11/30/2021: 360 shares +3 more

6 metrics

Largest common stock block to be sold 10,000 shares Common stock acquired via option exercise dated 09/01/2026 listed as securities to be sold

ESPP acquisition 05/31/2021 1,010 shares Common stock acquired through ESPP on 05/31/2021 listed as securities to be sold

ESPP acquisition 11/30/2021 360 shares Common stock acquired through ESPP on 11/30/2021 listed as securities to be sold

ESPP acquisition 05/31/2022 981 shares Common stock acquired through ESPP on 05/31/2022 listed as securities to be sold

ESPP acquisition 11/30/2022 146 shares Common stock acquired through ESPP on 11/30/2022 listed as securities to be sold

ESPP acquisition 05/31/2023 690 shares Common stock acquired through ESPP on 05/31/2023 listed as securities to be sold

Key Terms

Rule 144, Form 144, Option Exercise, ESPP, +1 more

5 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Form 144 regulatory

"144: Filer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Option Exercise financial

"Common Stock | 09/01/2026 | Option Exercise | Issuer"

ESPP financial

"Common Stock | 05/31/2021 | ESPP | Issuer"

An Employee Stock Purchase Plan (ESPP) is a company program that lets employees buy the company’s shares at a reduced price, usually by setting aside a small portion of their pay over time. It matters to investors because it encourages employees to own part of the business—like giving staff a discounted membership— which can boost commitment and performance, while also potentially increasing the number of shares available and affecting shareholder value.

attorney-in-fact regulatory

"as attorney-in-fact for Rong Zhou"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

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

What type of filing did AMPH submit related to Rong Zhou?

The submission is a Form 144 notice relating to planned sales of Amphastar Pharmaceuticals, Inc. common stock by Rong Zhou, a Vice President, in reliance on Rule 144 resale provisions.

How many AMPH shares are covered by the largest single block in this Form 144?

The largest single block covered is 10,000 shares of Amphastar common stock, identified as acquired through an option exercise dated 09/01/2026 and listed as securities to be sold under this notice.

What other AMPH share acquisitions are noted besides the option exercise?

In addition to the 10,000-share option exercise, the notice lists multiple smaller acquisitions of Amphastar common stock through the company’s ESPP on 05/31/2021 (1,010 shares), 11/30/2021 (360 shares), 05/31/2022 (981 shares), 11/30/2022 (146 shares), and 05/31/2023 (690 shares).

On which market is Amphastar Pharmaceuticals, Inc. common stock listed according to this filing?

The common stock referenced in this Form 144 is listed on NASDAQ, as stated in the securities information section identifying the class of securities as Amphastar common stock traded on that market.

Who is acting for Rong Zhou in connection with this AMPH Form 144?

The signature block shows that UBS Financial Services Inc. signed the notice as attorney-in-fact for Rong Zhou, with the signature by Mijo Suric on behalf of UBS Financial Services Inc.

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

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Available on EDGAR 09/01/2026 - 04:26 PM EDT Accepted by SEC EDGAR 09/01/2026 - 04:25 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001645326
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Amphastar Pharmaceuticals, Inc.
SEC File Number	001-36509
Address of Issuer	11570 SIXTH STREET Rancho Cucamonga CALIFORNIA 91730
Phone	909-980-9484
Name of Person for Whose Account the Securities are To Be Sold	Rong Zhou
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Vice President

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common Stock	UBS Financial Services Inc 1000 Harbor Blvd 3rd Floor Weehawken NJ 07086	13187	290114	44092919	09/01/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common Stock	09/01/2026	Option Exercise	Issuer			10000	09/01/2026	Cash
Common Stock	05/31/2021	ESPP	Issuer			1010	05/31/2021	Cash
Common Stock	11/30/2021	ESPP	Issuer			360	11/30/2021	Cash
Common Stock	05/31/2022	ESPP	Issuer			981	05/31/2022	Cash
Common Stock	11/30/2022	ESPP	Issuer			146	11/30/2022	Cash
Common Stock	05/31/2023	ESPP	Issuer			690	05/31/2023	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	09/01/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/Mijo Suric, for UBS Financial Services Inc, as attorney-in-fact for Rong Zhou
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)