BIOGEN INC (BIIB) Stock Institutional Trading Activity


BIOGEN INC (BIIB) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Renaissance Technologies LLC, Causeway Capital Management, Sequoia Financial Advisors, Hillman Value Fund, and Parnassus Endeavor Fund. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q4 2023Hillman Value FundBuy17034,476$8,921,355
Q3 2023Mairs & Power Growth FundSell-75950$244,160
Q3 2023Renaissance Technologies LLCSell-23,1401,086,397$279,215
Q3 2023Sequoia Financial AdvisorsBuy452,043$525,072
Q3 2023Hillman Value FundBuy4,89534,306$8,816,985
Q3 2023Parnassus Endeavor FundBuy54,934360,742$92,714,301
Q2 2023Renaissance Technologies LLCSell-154,3001,109,537$316,052
Q2 2023Sequoia Financial AdvisorsBuy2341,998$569,131
Q2 2023Hillman Value FundSell-12529,411$8,377,723
Q2 2023Hancock Classic ValueSell-7661,618$460,887
Q1 2023Renaissance Technologies LLCBuy263,5611,263,837$351,385
Q1 2023Sequoia Financial AdvisorsBuy151,764$490,445
Q1 2023Hillman Value FundSell-54029,536$8,211,894
Q4 2022Renaissance Technologies LLCSell-154,2311,000,276$276,996
Q4 2022Sequoia Financial AdvisorsSell-12,1471,749$484,333
Q4 2022Hillman Value FundSell-1,67830,076$8,328,646
Q4 2022Parnassus Endeavor FundSell-41,943305,808$84,684,351
Q3 2022Hillman Value FundSell-11,26531,754$8,479
Q3 2022Parnassus Endeavor FundSell-104,302347,751$92,850
Q3 2022Renaissance Technologies LLCSell-391,5001,154,507$308,253
Q2 2022Hillman Value FundBuy34043,019$8,774
Q2 2022Renaissance Technologies LLCBuy501,8001,546,007$315,293
Q1 2022Longleaf PartnersSell-15,561842,962$177,528
Q1 2022Hillman Value FundBuy15,48842,679$8,988
Q1 2022Renaissance Technologies LLCSell-29,6001,044,207$219,910
Q1 2022Hancock Classic ValueSell-4732,384$502
Q4 2021Longleaf PartnersBuy254,633858,523$205,977
Q4 2021Hillman Value FundSell-1,09827,191$6,523
Q4 2021Renaissance Technologies LLCBuy92,1001,073,807$257,628
Q3 2021Hillman Value FundBuy1,05028,289$8,005

Frequently asked questions about BIIB activity

  • Which institutional owners are buying BIIB?

    Institutional owners buying BIIB include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in BIIB activity?

    "Buy" means an investor increased their reported position in BIIB compared to the prior reporting period. This reflects growing exposure to BIOGEN INC (BIIB) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in BIIB increasing?

    Institutional interest in BIIB can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.