Summary
Updated Aug 31, 2026
Brian S. Posner files SEC Form 4 reports at Dyne Therapeutics, Inc. (DYN). 13 SEC Form 4 filings on record going back to 2025, most recently on 9 June 2026. Most recent open-market trade: bought $34K of DYN on 9 June 2026. Lifetime open-market purchases: $292K. Lifetime open-market sales: $145K. Historical track record: 4/5 stars across 6 tracked purchases.
Recent Transactions
12Every recent SEC Form 4 transaction Brian S. Posner has reported, most recent first.
Track Record
InsiderAlpha computes a forward-return-based score for every insider with enough Form 4 purchase history. The metrics below reflect realized performance after each tracked open-market purchase.
| Metric | Value |
|---|---|
| InsiderAlpha rating | ★★★★☆ (4/5) |
| Total purchases tracked | 6 |
| Purchases with forward-return data | 6 |
| 30-day win rate | 83% |
| 90-day win rate | 67% |
| Avg 5-day return | +6.77% |
| Avg 30-day return | +9.16% |
| Avg 90-day return | +21.27% |
| Best 30-day return | +23.49% |
Trading Pattern
InsiderAlpha's records for Brian S. Posner go back to 2025: 13 primary Form 4 filings, an average of 6.5 per year. The typical open-market purchase is $37K (8 buys totaling $292K). The largest single buy on record is $45K of DYN in 2026. Sales side: 3 recorded sales totaling $145K, so the filing history runs buy-heavy by dollar value. 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 Brian S. Posner 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
- John M. Pasquesi - $19.97M of ACGL open-market activity in the last 12 months
- Maamoun Rajeh - $4.56M of ACGL open-market activity in the last 12 months
- Nicolas Papadopoulo - $2.11M of ACGL open-market activity in the last 12 months
- Francois Morin - $1.85M of ACGL 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 Brian S. Posner?
Brian S. Posner is a corporate insider of Dyne Therapeutics, Inc. (DYN). InsiderAlpha holds 13 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 Brian S. Posner submitted recently?
3 primary Form 4 filings in the last 90 days, covering 2 companies.
Has Brian S. Posner been buying or selling stock?
Recorded transactions: 8 open-market purchases ($292K) and 3 open-market sales ($145K) across all tracked filings.
How accurate is Brian S. Posner's historical track record?
Across 6 tracked purchases, Brian S. Posner averaged +9.2% avg 30-day return with a 83% 30-day win rate. InsiderAlpha rates the track record at 4/5 stars.
Where can I see all of Brian S. Posner'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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