Summary
Updated Aug 31, 2026
Robert Nelsen is Director, 10% Owner of Prime Medicine, Inc. (PRME). 5 SEC Form 4 filings on record going back to 2025, most recently on 8 June 2026. Most recent open-market trade: bought $10.00M of PRME on 1 August 2025. Lifetime open-market purchases: $10.00M.
Recent Transactions
1Every recent SEC Form 4 transaction Robert Nelsen has reported, most recent first.
Trading Pattern
InsiderAlpha's records for Robert Nelsen go back to 2025: 5 primary Form 4 filings, an average of 2.5 per year. The typical open-market purchase is $10.00M (1 buy totaling $10.00M). The largest single buy on record is $10.00M of PRME in 2025. 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 have reported open-market trades at the same companies as Robert Nelsen. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
- ARCH Venture Partners X, LLC - $10.00M of PRME open-market activity on record
- ARCH Venture Partners XII, LLC - $10.00M of PRME open-market activity on record
- GV 2021 GP, L.L.C. - $4.95M of PRME open-market activity on record
- David R. Liu - $53K of PRME open-market activity on record
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
Who is Robert Nelsen?
Robert Nelsen is a corporate insider, tracked as Director, 10% Owner of Prime Medicine, Inc. (PRME). InsiderAlpha holds 5 primary Form 4 filings for them, the earliest from 2025, updated as new SEC EDGAR filings are processed.
How many SEC Form 4 filings has Robert Nelsen submitted recently?
2 primary Form 4 filings in the last 90 days, covering 2 companies.
Has Robert Nelsen been buying or selling stock?
Recorded transactions: 1 open-market purchase ($10.00M) and 0 open-market sales across all tracked filings.
Where can I see all of Robert Nelsen'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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