MarketPeel
Insider Trading Intelligence
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Brian S. Posner

BIIB
DIRECTOR · BIOGEN INC. · CIK 0001372455
FILING MIX · LIFETIME81%/19%
BUYS
26
SELLS
6
TOTAL VALUE
$806.0K
COMPANIES
3
ACTIVE SINCE
May 2020
HOLDINGS NOW
32,675
AVG SELL PX
$27.46
TRADE KIND
SHOWING 32 / 32
Trades · vs SPY
Loading price series…
Performance · forward returns vs SPY
12 backtested trades · 8 horizons · 19 pendingHow are these numbers computed? →
Forward-return performance of every backtestable P/S trade by Brian S. Posner, measured at 8 horizons from 7 days to 2 years. Deduped per economic event so co-filings count once. Excess return = trade return minus SPY return over the same window.
HORIZONTRADESWIN RATEINSIDER RETURNSPY RETURNMEAN EXCESSMEDIAN EXCESST-STAT
7d12+66.67%+6.04%+0.17%+5.87%+1.92%—
14d12+75.00%+9.35%+1.30%+8.64%+2.61%—
30d12+75.00%+11.00%+3.65%+7.35%+0.68%—
60d12(1 pending)+63.64%+9.29%+5.90%+3.70%+7.40%—
90d12(1 pending)+54.55%+11.02%+9.51%+1.01%+1.87%—
180d12(5 pending)+85.71%+17.33%+10.43%+6.90%+13.32%—
1y12(6 pending)+83.33%+40.19%+15.87%+24.32%+28.10%—
2y12(6 pending)+66.67%+79.42%+31.22%+48.19%+54.90%—
How to read this: Insider Returnis the average raw return of the filer's trades over the horizon. SPY Return is what SPY did over those same windows — reference only, not a comparison. The headline alpha number is Mean Excess = Insider − SPY; green means the filer beat SPY, red means they trailed it. Win rate is the share of individual trades where the filer beat SPY. T-statvalues above 2 mean the alpha is unlikely to be chance given the sample size. "Pending" counts trades where the horizon hasn't elapsed yet; their stats are not included in the row average.
Holdings over time
BIIB · 8,175 shares · as of Jul 1, 2021
02,0444,0886,1318,1752021SHARES HELD
Trading cadence · quarterly flow
BUY ● SELL ●
2020
2020
2020
2021
2021
2021
2021
2022
2022
2022
2022
2023
2023
2023
2023
2024
2024
2024
2024
2025
2025
2025
2025
2026
2026
FLOW · 26 buys / 6 sellsCOVERAGE · 25 quarters
Form 4 filings · all activity
COMPANYTYPESHARESPRICEVALUEHELD AFTERTRADE DATEFILEDDETAILS
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
2,000$16.94$33.9K24,500Jun 8, 2026Jun 9, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
35,152——35,152Jun 5, 2026Jun 9, 2026 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
SALE
3,000$19.66$59.0K0Jun 3, 2026Jun 4, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
2,500$17.48$43.7K22,500Jun 3, 2026Jun 5, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
2,000$18.21$36.4K20,000May 26, 2026May 28, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
2,500$17.12$42.8K18,000May 20, 2026May 22, 2026 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
SALE
2,000$17.14$34.3K0May 11, 2026May 12, 2026 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
2,071——122,175May 5, 2026May 7, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
2,000$17.08$34.2K15,500Mar 30, 2026Apr 1, 2026 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
SALE
3,000$17.12$51.3K2,000Mar 11, 2026Mar 12, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
2,000$19.35$38.7K13,500Mar 11, 2026Mar 13, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASE
3,000$15.06$45.2K11,500Mar 6, 2026Mar 10, 2026 ↗View →
DYN
DYNE THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
70,000——70,000Oct 1, 2025Oct 2, 2025 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASE
1,000$17.34$17.3K5,000Aug 1, 2025Aug 4, 2025 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
1,564——120,104May 7, 2025May 8, 2025 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
1,455——118,540May 9, 2024May 13, 2024 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
1,714——117,085May 4, 2023May 5, 2023 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASE
2,000$17.60$35.2K4,000Oct 28, 2022Nov 1, 2022 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
2,642——115,371May 4, 2022May 5, 2022 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
2,642——112,729May 4, 2022May 5, 2022 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASE
2,000$19.23$38.5K2,000Apr 29, 2022May 2, 2022 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
SALE
2,000$25.00$50.0K0Sep 30, 2021Oct 1, 2021 ↗View →
BIIB
BIOGEN INC.
PURCHASEGRANT
Stock grant
775——8,175Jul 1, 2021Jul 2, 2021 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
SALE
4,000$25.24$101.0K2,000Jun 14, 2021Jun 15, 2021 ↗View →
BIIB
BIOGEN INC.
SALE
360$274.17$98.7K7,400Jun 4, 2021Jun 7, 2021 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
3,143——110,087May 6, 2021May 10, 2021 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
3,143——106,944May 6, 2021May 10, 2021 ↗View →
BIIB
BIOGEN INC.
PURCHASEGRANT
Stock grant
890——7,885Jun 3, 2020Jun 5, 2020 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASE
1,000$22.16$22.2K103,801May 13, 2020May 14, 2020 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
5,058——102,801May 7, 2020May 8, 2020 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASEGRANT
Stock grant
5,058——97,743May 7, 2020May 8, 2020 ↗View →
ACGL
ARCH CAPITAL GROUP LTD.
PURCHASE
1,000$23.72$23.7K92,685May 6, 2020May 8, 2020 ↗View →
Other insiders · BIIB
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About this filer
CIK 0001372455
ROLE
Director
PRIMARY
BIIB
COMPANIES
3
ACTIVE SINCE
May 2020
MARKETPEEL · /INSIDER/0001372455DATA · SEC EDGAR · FORM 4 · CONSOLIDATED TAPE
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