BlackRock
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BlackRock’s Biogen BIIB Stock Holding History

BlackRock’s Portfolio BIIB Stock Details BIIB Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2022
Q1 		– Sell
-15,000
Closed -$3.6M – 5815
2021
Q4 		$3.6M Buy
+15,000
New +$3.86M ﹤0.01% 4139
2016
Q4 		– Sell
-200
Closed -$63K – 3733
2016
Q3 		$63K Buy
+200
New +$59.2K ﹤0.01% 2853

Other funds holding BIIB

Primecap Management
Primecap Management Pasadena, California $127B AUM 44.11% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
Wellington Management Group
Wellington Management Group Boston, Massachusetts $535B AUM 26.23% 1-Year Est. Return
Morgan Stanley
Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return
JP Morgan Chase
JP Morgan Chase New York $1.56T AUM 27.86% 1-Year Est. Return
AQR Capital Management
AQR Capital Management Greenwich, Connecticut $218B AUM 29.41% 1-Year Est. Return

BlackRock's BIIB Position: Q1 2026 in Review

BlackRock increased its Biogen (BIIB) stake by 7.9% in Q1 2026, buying an estimated $214M and bringing the position to 15,974,601 shares worth $2.93B. The position accounts for 0.05% of the portfolio, ranked #310.

BlackRock first reported a position in BIIB in Q2 2013 and has held it in 52 quarters since. The position peaked at $5.83B in Q3 2018. 1,002 funds tracked by Wall St. Rank hold BIIB as of Q1 2026.

  • BlackRock held 15,974,601 shares of Biogen worth $2.93B as of Q1 2026.
  • BlackRock bought 1,163,231 Biogen shares in Q1 2026, an estimated $214M.
  • Biogen made up 0.05% of BlackRock's portfolio in Q1 2026, its #310 holding.
  • BlackRock first reported a position in Biogen in Q2 2013 and has held it in 52 quarters since.
  • BlackRock's Biogen position peaked at $5.83B in Q3 2018.
  • 1,002 funds tracked by Wall St. Rank held Biogen as of Q1 2026.

Based on BlackRock's 13F filing for Q1 2026, filed 13 May 2026.