Brian S. Posner is Director at BIOGEN INC. (BIIB). They have made 28 open-market trades across 6 companies since 2006, most recently 2026-06-08.
CIK 0001372455
21 open-market purchases totalling $1.2M since 2006, against 7 sales. Across 19 scored buys the stock is up 14.0% at ninety days, and 8.2 points ahead of the S&P over the same stretch.
19 scored purchases · one row per filing · discretionary only
| 7d | 30d | 90d | |
|---|---|---|---|
| Accuracy | 63% | 79% | 74% |
| Avg Move | +2.8% | +10.4% | +14.0% |
| Alpha | +3.2% | +8.7% | +8.2% |
| Scored | 19 | 19 | 19 |
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| DYN | BUY | 2026-06-08 | 2026-06-09 | $16.94 | $34K | +17.3% | +36.3% | +14.1% |
| DYN | BUY | 2026-06-03 | 2026-06-05 | $17.48 | $44K | +11.0% | +32.3% | +44.3% |
| ACGL | SELL | 2026-06-03 | 2026-06-04 | $19.66 | $59K | +3.2% | +13.5% | +9.5% |
| DYN | BUY | 2026-05-26 | 2026-05-28 | $18.21 | $36K | -5.1% | +12.6% | +39.7% |
| DYN | BUY | 2026-05-20 | 2026-05-22 | $17.12 | $43K | +1.0% | +14.5% | +42.6% |
| ACGL | SELL | 2026-05-11 | 2026-05-12 | $17.14 | $34K | +2.9% | -2.7% | +4.9% |
| DYN | BUY | 2026-03-30 | 2026-04-01 | $17.08 | $34K | +13.5% | -0.4% | +27.3% |
| DYN | BUY | 2026-03-11 | 2026-03-13 | $19.35 | $39K | +3.3% | +3.4% | -2.3% |
| ACGL | SELL | 2026-03-11 | 2026-03-12 | $17.12 | $51K | -1.6% | +2.1% | -4.0% |
| DYN | BUY | 2026-03-06 | 2026-03-10 | $15.06 | $45K | -11.1% | -2.0% | -14.9% |
| ACGL | BUY | 2025-08-01 | 2025-08-04 | $17.34 | $17K | +3.1% | +4.8% | -3.0% |
| ACGL | BUY | 2022-10-28 | 2022-11-01 | $17.60 | $35K | +2.9% | +8.3% | +16.0% |
| ACGL | BUY | 2022-04-29 | 2022-05-02 | $19.23 | $38K | -2.0% | +1.4% | -5.7% |
| ACGL | SELL | 2021-06-14 | 2021-06-15 | $25.24 | $101K | -0.2% | -3.6% | +1.3% |
| BIIB | SELL | 2021-06-04 | 2021-06-07 | $274.17 | $197K | -1.4% | -8.7% | -15.9% |
| ACGL | BUY | 2020-05-13 | 2020-05-15 | $22.16 | $22K | +21.7% | +29.6% | +35.6% |
| ACGL | BUY | 2020-05-06 | 2020-05-08 | $23.72 | $24K | +3.7% | +39.3% | +22.3% |
| BIIB | SELL | 2019-12-02 | 2019-12-03 | $292.35 | $617K | +2.3% | +1.4% | +13.0% |
| ACGL | BUY | 2018-11-28 | 2018-11-29 | $25.05 | $25K | -4.5% | -6.1% | +13.7% |
| ACGL | BUY | 2018-11-05 | 2018-11-06 | $22.45 | $56K | +1.1% | -0.7% | +7.3% |
| ACGL | BUY | 2018-05-03 | 2018-05-04 | $78.63 | $236K | -1.0% | +1.5% | +13.3% |
| BIVV | BUY | 2017-08-09 | 2017-08-10 | $59.19 | $59K | -0.3% | +0.2% | -4.2% |
| BIIB | SELL | 2017-06-09 | 2017-06-12 | $256.31 | $556K | +7.1% | +5.0% | +24.6% |
| BIVV | BUY | 2017-05-24 | 2017-05-24 | $53.86 | $108K | +5.9% | +14.6% | +3.2% |
| ACGL | BUY | 2016-11-18 | 2016-11-21 | $21.88 | $131K | +2.7% | +7.6% | +15.7% |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.
Counted per filing, not per execution lot — a purchase filled in several tranches is one decision.