Summary
Updated Aug 31, 2026
John Cox is CEO & President, Director of Dyne Therapeutics, Inc. (DYN). 10 SEC Form 4 filings on record going back to 2024, most recently on 17 August 2026. Most recent open-market trade: sold $131K of DYN on 17 August 2026. Lifetime open-market purchases: $911K. Lifetime open-market sales: $372K.
Recent Transactions
13Every recent SEC Form 4 transaction John Cox has reported, most recent first.
Trading Pattern
InsiderAlpha's records for John Cox go back to 2024: 10 primary Form 4 filings, an average of 3.3 per year. The typical open-market purchase is $911K (1 buy totaling $911K). The largest single buy on record is $911K of DYN in 2025. Sales side: 6 recorded sales totaling $372K, so the filing history runs buy-heavy by dollar value. 5 recorded transactions carry a Rule 10b5-1 flag, meaning they were pre-scheduled under a written trading plan rather than discretionary.
Other Insiders Active in the Same Stocks
Insiders who reported open-market trades in the last 12 months at the companies John Cox 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.
- Jason P. Rhodes - $124.92M of DYN open-market activity in the last 12 months
- Dirk Kersten - $38.57M of DYN open-market activity in the last 12 months
- Brian S. Posner - $275K of DYN open-market activity in the last 12 months
- Erick Lucera - $229K of DYN open-market activity in the last 12 months
- Douglas Kerr - $176K of DYN open-market activity in the last 12 months
- Johanna Friedl-Naderer - $32K of DYN 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 John Cox?
John Cox is a corporate insider, tracked as CEO & President, Director of Dyne Therapeutics, Inc. (DYN). InsiderAlpha holds 10 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 John Cox submitted recently?
2 primary Form 4 filings in the last 90 days, covering 1 company.
Has John Cox been buying or selling stock?
Recorded transactions: 1 open-market purchase ($911K) and 6 open-market sales ($372K) across all tracked filings.
Where can I see all of John Cox'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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