PEAK6’s Biogen BIIB Stock Holding History

PEAK6’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
2026 Q2	$20.4M	Buy	94,300 +61,100	+184%	+$11.7M	0.04%	330
2026 Q1	$6.09M	Sell	33,200 -72,000	-68%	-$13.3M	0.01%	802
2025 Q4	$18.5M	Sell	105,200 -25,500	-20%	-$4.17M	0.03%	396
2025 Q3	$18.3M	Buy	130,700 +71,000	+119%	+$9.6M	0.03%	452
2025 Q2	$7.5M	Buy	+59,700	New	+$7.44M	0.01%	764
2025 Q1	–	Sell	-12,700	Closed	-$1.94M	–	3014
2024 Q4	$1.94M	Buy	+12,700	New	+$2.14M	﹤0.01%	1437

Other funds holding BIIB

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Primecap Management Pasadena, California $169B AUM 114.72% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return

Wellington Management Group Boston, Massachusetts $580B AUM 38.23% 1-Year Est. Return

Norges Bank Oslo, Norway $1T AUM

Morgan Stanley New York $1.89T AUM 35.08% 1-Year Est. Return

PEAK6's BIIB Position: Q2 2026 in Review

PEAK6 reduced its Biogen (BIIB) stake by 48% in Q2 2026, selling an estimated $2.57M and leaving 14,752 shares worth $3.19M. The position accounts for 0.01% of the portfolio, ranked #1062.

PEAK6 first reported a position in BIIB in Q4 2024 and has held it in 5 quarters since. The position peaked at $5.16M in Q1 2026. 1,043 funds tracked by Wall St. Rank hold BIIB as of Q2 2026.

PEAK6 held 14,752 shares of Biogen worth $3.19M as of Q2 2026.
PEAK6 sold 13,414 Biogen shares in Q2 2026, an estimated $2.57M.
Biogen made up 0.01% of PEAK6's portfolio in Q2 2026, its #1062 holding.
PEAK6 first reported a position in Biogen in Q4 2024 and has held it in 5 quarters since.
PEAK6's Biogen position peaked at $5.16M in Q1 2026.
1,043 funds tracked by Wall St. Rank held Biogen as of Q2 2026.

Based on PEAK6's 13F filing for Q2 2026, filed 13 Aug 2026.