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 2025Renaissance Technologies LLCSell-565,210399,196$70,254,504
Q4 2025Causeway Capital ManagementSell-46,417521,101$91,708,545
Q3 2025Sequoia Financial AdvisorsBuy4,5699,096$1,274,137
Q3 2025Hillman Value FundSell-3,61838,354$5,372,628
Q3 2025Causeway Capital ManagementBuy74,163567,518$79,497,885
Q3 2025Renaissance Technologies LLCSell-80,700964,406$135,093,992
Q2 2025Sequoia Financial AdvisorsBuy1,5104,527$568,499
Q2 2025Hillman Value FundSell-2,05341,972$5,271,263
Q2 2025Causeway Capital ManagementBuy59,838493,355$61,960,403
Q2 2025Renaissance Technologies LLCBuy240,6001,045,106$131,254,863
Q1 2025Sequoia Financial AdvisorsSell-93,017$412,848
Q1 2025Hillman Value FundBuy95944,025$6,024,381
Q1 2025Causeway Capital ManagementBuy151,815433,517$59,322,464
Q1 2025Renaissance Technologies LLCSell-387,700804,506$110,088,601
Q4 2024Sequoia Financial AdvisorsBuy7293,026$462,715
Q4 2024Hillman Value FundBuy7,81343,066$6,585,653
Q4 2024Causeway Capital ManagementSell-122,742281,702$43,077,910
Q4 2024Renaissance Technologies LLCBuy239,5001,192,206$182,312,142
Q3 2024Sequoia Financial AdvisorsSell-2852,297$445,224
Q3 2024Hillman Value FundSell-70135,253$6,833,442
Q3 2024Parnassus Endeavor FundBuy770361,512$70,075,486
Q3 2024Renaissance Technologies LLCBuy334,600952,706$184,672,531
Q2 2024Sequoia Financial AdvisorsBuy2412,582$598,527
Q2 2024Hillman Value FundBuy16235,954$8,334,856
Q2 2024Renaissance Technologies LLCSell-266,598618,106$143,289,333
Q1 2024Renaissance Technologies LLCBuy126,098884,704$190,769
Q1 2024Sequoia Financial AdvisorsSell-3272,341$504,790
Q1 2024Hillman Value FundBuy1,31635,792$7,717,829
Q4 2023Renaissance Technologies LLCSell-327,791758,606$196,304
Q4 2023Sequoia Financial AdvisorsBuy6252,668$690,399

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.