Atom Investors’s Biogen BIIB Stock Holding History

Atom Investors’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	$4.54M	Buy	24,749 +3,029	+14%	+$558K	0.32%	92
2025 Q4	$3.82M	Buy	21,720 +19,498	+877%	+$3.19M	0.3%	113
2025 Q3	$311K	Buy	+2,222	New	+$300K	0.02%	441
2025 Q1	–	Sell	-2,745	Closed	-$420K	–	512
2024 Q4	$420K	Buy	+2,745	New	+$463K	0.05%	334
2022 Q1	–	Sell	-2,686	Closed	-$644K	–	212
2021 Q4	$644K	Buy	+2,686	New	+$691K	0.11%	141
2021 Q1	–	Sell	-42,471	Closed	-$10.4M	–	257
2020 Q4	$10.4M	Buy	42,471 +23,437	+123%	+$6.05M	1.05%	23
2020 Q3	$5.4M	Buy	19,034 +7,158	+60%	+$2M	0.51%	41
2020 Q2	$3.18M	Sell	11,876 -20,871	-64%	-$6.27M	0.21%	93
2020 Q1	$10.4M	Buy	32,747 +3,360	+11%	+$1.02M	0.91%	29
2019 Q4	$8.72M	Sell	29,387 -18,176	-38%	-$5.04M	0.71%	45
2019 Q3	$11.1M	Buy	47,563 +24,444	+106%	+$5.69M	0.76%	35
2019 Q2	$5.41M	Buy	23,119 +20,162	+682%	+$4.66M	0.35%	88
2019 Q1	$699K	Buy	+2,957	New	+$931K	0.06%	220

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

Atom Investors's BIIB Position: Q1 2026 in Review

Atom Investors increased its Biogen (BIIB) stake by 14% in Q1 2026, buying an estimated $558K and bringing the position to 24,749 shares worth $4.54M. The position accounts for 0.32% of the portfolio, ranked #92.

Atom Investors first reported a position in BIIB in Q1 2019 and has held it in 13 quarters since. The position peaked at $11.1M in Q3 2019. 1,002 funds tracked by Wall St. Rank hold BIIB as of Q1 2026.

Atom Investors held 24,749 shares of Biogen worth $4.54M as of Q1 2026.
Atom Investors bought 3,029 Biogen shares in Q1 2026, an estimated $558K.
Biogen made up 0.32% of Atom Investors's portfolio in Q1 2026, its #92 holding.
Atom Investors first reported a position in Biogen in Q1 2019 and has held it in 13 quarters since.
Atom Investors's Biogen position peaked at $11.1M in Q3 2019.
1,002 funds tracked by Wall St. Rank held Biogen as of Q1 2026.

Based on Atom Investors's 13F filing for Q1 2026, filed 15 May 2026.