Brian S. Posner

Brian S. Posner, listed as board member, has filed trades across 4 companies (mainly through SEC (Form 4)), most often in Arch Capital Group Ltd., Biogen Inc. and Dyne Therapeutics, Inc. We count 57 filings; the first trade dates from 6 May 2016 and the latest from 2 October 2026.

In open-market terms, that means 22 purchases worth €940k on one side and 7 sales worth €817k on the other. Taken together, the purchases exceed the sales by €123k. A purchase on the market is a deliberate choice to commit personal money, which is why it draws more attention than a grant. Other entries cover 22 share grants. In 2026 alone, the filings show 8 purchases and 3 sales.

A typical purchase (the median) is worth €35k. Scaled by market value, the purchases weigh a median 0.0009% of market cap (sample: 4 purchases). Of 22 purchases, 1 formed part of a group of insiders buying within 30 days of each other. When several insiders buy within a few weeks of each other, analysts speak of a cluster purchase. After 9 purchases with a full 90-day history, the hit rate stands at 67% and the median 90-day move at +14.5%. They describe history only and say nothing certain about the share price ahead.

The newest entry dates from 6 October 2026: an open-market purchase of €36k, in Dyne Therapeutics, Inc. Filings reach the SEC (Form 4) feed a median of 1 day after the trade. US insiders must file a Form 4 within two business days of a trade. This summary is built from SEC (Form 4) disclosures alone and does not predict where the share price will go.