Summary
Updated Aug 31, 2026
Richard K. Prins is Director of Amphastar Pharmaceuticals, Inc. (AMPH). 9 SEC Form 4 filings on record going back to 2024, most recently on 12 August 2026. Most recent open-market trade: sold $162K of AMPH on 12 August 2026. Lifetime open-market sales: $957K.
Recent Transactions
15Every recent SEC Form 4 transaction Richard K. Prins has reported, most recent first.
Trading Pattern
InsiderAlpha's records for Richard K. Prins go back to 2024: 9 primary Form 4 filings, an average of 3.0 per year. No transaction on record carries a Rule 10b5-1 flag - the filings look discretionary rather than pre-scheduled, which makes their timing more informative as a signal.
Other Insiders Active in the Same Stocks
Insiders who reported open-market trades in the last 12 months at the companies Richard K. Prins files at. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
- Floyd F. Petersen - $484K of AMPH open-market activity in the last 12 months
- William J. Peters - $184K of AMPH open-market activity in the last 12 months
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
Who is Richard K. Prins?
Richard K. Prins is a corporate insider, tracked as Director of Amphastar Pharmaceuticals, Inc. (AMPH). InsiderAlpha holds 9 primary Form 4 filings for them, the earliest from 2024, updated as new SEC EDGAR filings are processed.
How many SEC Form 4 filings has Richard K. Prins submitted recently?
2 primary Form 4 filings in the last 90 days, covering 1 company.
Has Richard K. Prins been buying or selling stock?
Recorded transactions: 0 open-market purchases and 4 open-market sales ($957K) across all tracked filings.
Where can I see all of Richard K. Prins's SEC filings?
All Form 4 filings, transaction values, and 10b5-1 plan flags are listed on this page and updated in real time as new SEC EDGAR filings are processed.
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