Rossby Financial’s Biogen BIIB Stock Holding History

Rossby 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
2026 Q2	$21.2K	Buy	98 +45	+85%	+$8.61K	﹤0.01%	946
2026 Q1	$9.74K	Buy	53 +39	+279%	+$7.19K	﹤0.01%	1263
2025 Q4	$2.46K	Buy	+14	New	+$2.29K	﹤0.01%	1308

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

Rossby Financial's BIIB Position: Q2 2026 in Review

Rossby Financial increased its Biogen (BIIB) stake by 85% in Q2 2026, buying an estimated $8.61K and bringing the position to 98 shares worth $21.2K. The position accounts for ﹤0.01% of the portfolio, ranked #946.

Rossby Financial first reported a position in BIIB in Q4 2025 and has held it in 3 quarters since. 1,043 funds tracked by Wall St. Rank hold BIIB as of Q2 2026.

Rossby Financial held 98 shares of Biogen worth $21.2K as of Q2 2026.
Rossby Financial bought 45 Biogen shares in Q2 2026, an estimated $8.61K.
Biogen made up ﹤0.01% of Rossby Financial's portfolio in Q2 2026, its #946 holding.
Rossby Financial first reported a position in Biogen in Q4 2025 and has held it in 3 quarters since.
1,043 funds tracked by Wall St. Rank held Biogen as of Q2 2026.

Based on Rossby Financial's 13F filing for Q2 2026, filed 4 Aug 2026.