Amphstar Pharmaceuticals, Inc. (AMPH)Director sold ~$162K

~$162K

Approx. value · 7,973 sh @ $20.30

30K

Holds after · shares reported

Traded

Aug 11, 2026

Filed

Aug 12, 2026

The story around this disclosure

Every dated public record OQRO holds about the company from 60 days before to 120 days after, oldest first. It shows what was going on; none of it is a stated reason for the trade.

1. Jul 9, 2026Company filing · Form 8-K · Executive changeChanged a top executive or board member“On July 9, 2026, the Board of Directors (the “Board”) of Amphastar Pharmaceuticals, Inc. (the “Company”), upon the recommendation of the Nominating and Corporate Governance Committee of the Board (the “Nominating Committee”), approved an increase to the authorized number of directors permitted to serve on the Board from ten (10) to eleven (11) directors and appointed Anthony Pierce, to serve as a Class III director,…”
2. Aug 6, 2026Company filing · Form 8-K · ResultsReported its results
3. Aug 7, 2026InsiderCFO sold ~$184K of AMPH shares in the open market
4. Aug 11, 2026 · this disclosureInsiderDirector sold ~$162K of AMPH shares in the open market

What came next

1. Sep 2, 2026InsiderOfficer sold ~$75K of AMPH shares in the open market
2. Sep 16, 2026InsiderOfficer sold ~$239K of AMPH shares in the open market
3. Sep 21, 2026InsiderCFO sold ~$103K of AMPH shares in the open market

How to read SEC Form 4

Form 4 is the filing that officers, directors and owners of more than 10% of a US-listed company must send to the SEC within two business days after they buy, sell or otherwise change their holding of the company's stock.

Full guide: What is an SEC Form 4?

What else is on file for Amphstar Pharmaceuticals, Inc.

For Amphstar Pharmaceuticals, Inc., OQRO holds 5 insider filings (SEC Form 4 or Form 144) dated in the last 90 days.

These are records OQRO holds, counted by their date, not a measure of how much trading took place. Routine paperwork such as option exercises and tax withholding is left out. Everything for the company is on its AMPH page.

Other recent filings by Richard K Prins, Director

• SEC Form 4 at Amphstar Pharmaceuticals, Inc. (AMPH)Nov 26, 2025
• SEC Form 4 at Amphstar Pharmaceuticals, Inc. (AMPH)Dec 12, 2024
• SEC Form 4 at Amphstar Pharmaceuticals, Inc. (AMPH)Nov 13, 2024

The full history of Richard K Prins, Director is on the profile page.

How this filing works

• SEC Form 4
• Open-market purchase
• Rule 10b5-1 trading plans

Other disclosures at Amphstar Pharmaceuticals, Inc.

• SEC Form 4Sep 23, 2026
• SEC Form 4Sep 17, 2026
• SEC Form 4Sep 3, 2026
• SEC Form 4Aug 11, 2026
• SEC Form 13F-HRMay 13, 2026
• SEC Form 13F-HRFeb 9, 2026

Everything OQRO holds on this company is on its AMPH page.