Key facts
- This page summarizes Richard K. Prins's Form 4 filing for Amphastar Pharmaceuticals, Inc. (AMPH).
- 1 reported transaction and 0 derivative rows are listed below.
- Accepted by SEC: 12 Aug 2026, 18:14.
Richard K. Prins - 11 Aug 2026 Form 4 Insider Report for Amphastar Pharmaceuticals, Inc. (AMPH)
- Reporting relationship
- Director
- Issuer ticker
- AMPH
- Reported as of
- 11 Aug 2026
- Net transaction value
- -$161,852
- SEC form
- 4
- Accepted by SEC
- 12 Aug 2026, 18:14:55 UTC
- Prior SEC filing
- 06 Apr 2026
- Source filing
- View source filing
- Reporting owner signature
- /s/ Eva Wen, by power of attorney
Source evidence
Original filing metadata and source links for verification.
4 source fields
Reporting owner
1 detail
Key filing fact
Richard K. Prins filed Form 4 for Amphastar Pharmaceuticals, Inc. (AMPH) on 12 Aug 2026.
Change
- Previous filing in this sequence was filed on 06 Apr 2026.
- Current net transaction value: -$161,852.
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
View source filing
Ownership activity is grounded in SEC Form 4 disclosures.
Reporting Owners (1)
CIK 0001047579
Primary reporting owner
PRINS RICHARD K
- Relationship
- Director
- Address
- C/O AMPHASTAR PHARMACEUTICALS, INC., 11570 6TH STREET, RANCHO CUCAMONGA
- Signature
- /s/ Eva Wen, by power of attorney
- Signature date
- 12 Aug 2026
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
AMPH
transaction
Common Stock
Sale
- Transaction value
- $161,852
- Shares
- -7,973
- Change %
- -21%
- Price
- $20.30
- Shares after
- 29,625
- Date
- 11 Aug 2026
- Ownership
- Direct
* marks a reported price that did not pass the local price check.