Rong Zhou - 09 Mar 2026 Form 4 Insider Report for Amphastar Pharmaceuticals, Inc. (AMPH)

Reporting relationship: SENIOR EVP, PRODUCTION CENTER
Issuer ticker: AMPH
Reported as of: 09 Mar 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 11 Mar 2026, 20:15:55 UTC
Prior SEC filing: 10 Mar 2026
Next SEC filing: 17 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Eva Wen, by power of attorney

Key filing fact

Rong Zhou filed Form 4 for Amphastar Pharmaceuticals, Inc. (AMPH) on 11 Mar 2026.

Key facts

This page summarizes Rong Zhou's Form 4 filing for Amphastar Pharmaceuticals, Inc. (AMPH).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 11 Mar 2026, 20:15.

Change

Previous filing in this sequence was filed on 10 Mar 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001645326 Primary reporting owner

Zhou Rong

Relationship: SENIOR EVP, PRODUCTION CENTER
Address: C/O AMPHASTAR PHARMACEUTICALS, INC., 11570 6TH STREET, RANCHO CUCAMONGA
Signature: /s/ Eva Wen, by power of attorney
Signature date: 11 Mar 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

AMPH transaction

Common Srock

Award

Transaction value
Shares: +39,432
Change %: +29%
Price: $0.000000^*
Shares after: 174,994
Date: 09 Mar 2026
Ownership: Direct
Footnotes: F1

AMPH transaction

Common Stock

Tax liability

Transaction value
Shares: -2,215
Change %: -1.3%
Price: $18.91^*
Shares after: 172,779
Date: 10 Mar 2026
Ownership: Direct
Footnotes: F2

AMPH holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 99,668
Date: 09 Mar 2026
Ownership: See footnote
Footnotes: F3

AMPH holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 5,000
Date: 09 Mar 2026
Ownership: See footnote
Footnotes: F4

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

AMPH transaction Derivative

Employee Stock Option (right to buy)

Award

Transaction value
Shares: +81,341
Change %
Price: $0.000000^*
Shares after: 81,341
Date: 09 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 81,341
Exercise price: $19.21
Footnotes: F5

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 5 footnotes

Footnote F1

The reported shares are represented by restricted stock units, or RSUs, which vest in four equal annual installments beginning on March 9, 2027.

Footnote F2

The reported shares were withheld to satisfy the reporting person's tax liability in connection with the vesting of RSUs.

Footnote F3

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

Footnote F4

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

Footnote F5

The shares subject to the option vest in four equal annual installments beginning on March 9, 2027.