Hudson Bay Capital Management
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Hudson Bay Capital Management’s Biogen BIIB Stock Holding History

Hudson Bay Capital Management’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
2019
Q2 		– Sell
-30,000
Closed -$7.09M – 440
2019
Q1 		$7.09M Buy
30,000
+10,000
+50% +$3.15M 0.09% 217
2018
Q4 		$6.02M Buy
+20,000
New +$6.38M 0.08% 235
2017
Q2 		– Sell
-10,000
Closed -$2.73M – 548
2017
Q1 		$2.73M Sell
10,000
-105,500
-91% -$29.8M 0.04% 395
2016
Q4 		$32.8M Buy
115,500
+27,400
+31% +$8.12M 0.68% 22
2016
Q3 		$27.6M Buy
+88,100
New +$26.1M 0.67% 29

Other funds holding BIIB

Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Primecap Management
Primecap Management Pasadena, California $169B AUM 114.72% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
Wellington Management Group
Wellington Management Group Boston, Massachusetts $580B AUM 38.23% 1-Year Est. Return
Norges Bank
Norges Bank Oslo, Norway $1T AUM
Morgan Stanley
Morgan Stanley New York $1.89T AUM 35.08% 1-Year Est. Return

Hudson Bay Capital Management's BIIB Position: Q2 2026 in Review

Hudson Bay Capital Management reduced its Biogen (BIIB) stake by 55% in Q2 2026, selling an estimated $21.3M and leaving 90,000 shares worth $19.4M. The position accounts for 0.05% of the portfolio, ranked #222.

Hudson Bay Capital Management first reported a position in BIIB in Q3 2016 and has held it in 36 quarters since. The position peaked at $58.2M in Q3 2024. 1,043 funds tracked by Wall St. Rank hold BIIB as of Q2 2026.

  • Hudson Bay Capital Management held 90,000 shares of Biogen worth $19.4M as of Q2 2026.
  • Hudson Bay Capital Management sold 111,367 Biogen shares in Q2 2026, an estimated $21.3M.
  • Biogen made up 0.05% of Hudson Bay Capital Management's portfolio in Q2 2026, its #222 holding.
  • Hudson Bay Capital Management first reported a position in Biogen in Q3 2016 and has held it in 36 quarters since.
  • Hudson Bay Capital Management's Biogen position peaked at $58.2M in Q3 2024.
  • 1,043 funds tracked by Wall St. Rank held Biogen as of Q2 2026.

Based on Hudson Bay Capital Management's 13F filing for Q2 2026, filed 14 Aug 2026.