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 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

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

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

Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return

VCM

Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM

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

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

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

JP Morgan Chase New York $1.56T AUM 27.86% 1-Year Est. Return

Rossby Financial's BIIB Position: Q1 2026 in Review

Rossby Financial increased its Biogen (BIIB) stake by 279% in Q1 2026, buying an estimated $7.19K and bringing the position to 53 shares worth $9.74K. The position accounts for ﹤0.01% of the portfolio, ranked #1263.

Rossby Financial first reported a position in BIIB in Q4 2025 and has held it in 2 quarters since. 1,002 funds tracked by Wall St. Rank hold BIIB as of Q1 2026.

Rossby Financial held 53 shares of Biogen worth $9.74K as of Q1 2026.
Rossby Financial bought 39 Biogen shares in Q1 2026, an estimated $7.19K.
Biogen made up ﹤0.01% of Rossby Financial's portfolio in Q1 2026, its #1263 holding.
Rossby Financial first reported a position in Biogen in Q4 2025 and has held it in 2 quarters since.
1,002 funds tracked by Wall St. Rank held Biogen as of Q1 2026.

Based on Rossby Financial's 13F filing for Q1 2026, filed 11 May 2026.