Magnetar Financial’s Biogen BIIB Stock Holding History

Magnetar Financial’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
2014 Q1	–	Sell	-1,100	Closed	-$308K	–	229
2013 Q4	$308K	Buy	1,100 +200	+22%	+$51.7K	0.01%	205
2013 Q3	$217K	Buy	+900	New	+$201K	﹤0.01%	463

Other funds holding BIIB

Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return

Primecap Management Pasadena, California $127B AUM 44.11% 1-Year Est. Return

BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return

Wellington Management Group Boston, Massachusetts $535B AUM 26.23% 1-Year Est. Return

Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return

Point72 Asset Management Stamford, Connecticut $78.1B AUM 55.25% 1-Year Est. Return

Invesco Atlanta, Georgia $1.02T AUM 30.18% 1-Year Est. Return

Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return

AQR Capital Management Greenwich, Connecticut $218B AUM 29.41% 1-Year Est. Return

Magnetar Financial's BIIB Position: Q3 2025 in Review

Magnetar Financial sold out of Biogen (BIIB) in Q3 2025, closing a stake of 2,484 shares — an estimated $312K sold.

Magnetar Financial first reported a position in BIIB in Q1 2015 and held it in 19 quarters. The position peaked at $10M in Q3 2021. 905 funds tracked by Wall St. Rank hold BIIB as of Q3 2025.

Magnetar Financial reported no remaining Biogen position as of Q3 2025 after selling out during the quarter.
Magnetar Financial sold 2,484 Biogen shares in Q3 2025, an estimated $312K.
Magnetar Financial first reported a position in Biogen in Q1 2015 and held it in 19 quarters.
Magnetar Financial's Biogen position peaked at $10M in Q3 2021.
905 funds tracked by Wall St. Rank held Biogen as of Q3 2025.

Based on Magnetar Financial's 13F filing for Q3 2025, filed 13 Nov 2025.