Summary
Updated Aug 31, 2026
Robert S. Henderson is Director of Perimeter Solutions, Inc. (PRM). 2 SEC Form 4 filings on record going back to 2024, most recently on 2 March 2026.
Recent Transactions
1Every recent SEC Form 4 transaction Robert S. Henderson has reported, most recent first.
Trading Pattern
InsiderAlpha's records for Robert S. Henderson go back to 2024: 2 primary Form 4 filings, an average of 0.7 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 Robert S. Henderson 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.
- WINDACRE PARTNERSHIP LLC - $391.22M of PRM open-market activity in the last 12 months
- Jeffrey Emery - $13.25M of PRM open-market activity in the last 12 months
- Kyle Sable - $11.72M of PRM open-market activity in the last 12 months
- William N. Thorndike Jr. - $7.60M of PRM open-market activity in the last 12 months
- Haitham Khouri - $7.28M of PRM open-market activity in the last 12 months
- Noriko Yokozuka - $3.91M of PRM 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 Robert S. Henderson?
Robert S. Henderson is a corporate insider, tracked as Director of Perimeter Solutions, Inc. (PRM). InsiderAlpha holds 2 primary Form 4 filings for them, the earliest from 2024, updated as new SEC EDGAR filings are processed.
When did Robert S. Henderson last file a Form 4?
The most recent primary Form 4 on record is dated 2 March 2026, one of 2 filings going back to 2024.
Where can I see all of Robert S. Henderson'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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