Brian S Posner
CIK 1372455 · last filed 2026-10-06
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
Charts
Trading activity, where the exposure sits, and each trade against the stock price.
BIIB price and trades
Daily close with each Form 4 filing on this company marked: green = open-market buy, red = open-market sale, purple = grants, exercises, gifts and other non-market transactions. Marker size scales with the dollar value.
Shares held
Shares owned after each reported transaction on this company (direct holdings as reported).
Open-market buying and selling
by monthDollar value of open-market purchases (code P, up) and sales (code S, down) across all companies, by filing month. Grants, exercises and gifts are excluded.
Exposure by company
latestMost recently reported shares × current price. Faded bars (*) have had no filing in 3 years, so the person may no longer hold them. Click a bar to chart that company.
Filer Profile
CAMBRIDGE, MA 02142
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| DYN | Director | 27,000 | $16.79 | $453.3K | $314.8K | 9 | 2026-10-06 |
| ACGLO | Director | 0 | $17.91 | $0 | $208.3K | 21 | 2026-06-04 |
| BIIB | Director | 8,175 | $251.07 | $2.05M | -$6.74M | 26 | 2021-07-02 |
| Bioverativ Inc. (BIVV) Delisted | Director | 0 | — | — | $166.9K | 7 | 2018-03-08 |
| ACGL | Director | 18,000 | $100.01 | $1.80M | $316.4K | 13 | 2018-01-02 |
| BG Medicine, Inc. (BGMD) Delisted | Director | 5,000 | — | — | $52.0K | 4 | 2013-06-14 |
| ANADYS PHARMACEUTICALS INC (ANDS) Delisted | Director | — | — | — | $0 | 1 | 2011-08-24 |
Recent Filings · Page 8 of 9
81 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2012-05-11 | ACGL | Grant (A) | +3,888 | $0 | EDGAR |
| 2012-02-15 | BG Medicine, Inc. (BGMD) Delisted | Grant (A) | — | $0 | EDGAR |
| 2011-08-31 | BIIB | Mixed | — | -$317.2K | EDGAR |
| 2011-08-24 | ANADYS PHARMACEUTICALS INC (ANDS) Delisted | Grant (A) | — | $0 | EDGAR |
| 2011-06-02 | BIIB | Grant (A) | +2,900 | $0 | EDGAR |
| 2011-05-27 | BIIB | Mixed | — | -$697.2K | EDGAR |
| 2011-05-09 | ACGL | Grant (A) | +1,326 | $0 | EDGAR |
| 2010-11-08 | ACGL | Grant (A) | +332 | $0 | EDGAR |
| 2010-06-10 | BIIB | Grant (A) | +5,735 | $0 | EDGAR |
| 2009-06-05 | BIIB | Grant (A) | +2,245 | $0 | EDGAR |
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.