Palo Alto Investors’s Biogen BIIB Stock Holding History

Palo Alto 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	$25.8M	Sell	140,719 -42,852	-23%	-$7.9M	3.95%	9
2025 Q4	$32.3M	Sell	183,571 -2,090	-1%	-$341K	4.5%	7
2025 Q3	$26M	Sell	185,661 -20,098	-10%	-$2.72M	4.81%	6
2025 Q2	$25.8M	Buy	205,759 +836	+0.4%	+$104K	5.5%	6
2025 Q1	$28M	Buy	204,923 +14,775	+8%	+$2.11M	5.34%	6
2024 Q4	$29.1M	Sell	190,148 -38,768	-17%	-$6.54M	4.51%	7
2024 Q3	$44.4M	Sell	228,916 -60,134	-21%	-$12.6M	5.76%	5
2024 Q2	$67M	Sell	289,050 -908	-0.3%	-$197K	7.76%	5
2024 Q1	$62.5M	Sell	289,958 -90,459	-24%	-$21.2M	7.05%	4
2023 Q4	$98.4M	Sell	380,417 -865	-0.2%	-$212K	8.87%	4
2023 Q3	$98M	Hold	381,282	–	–	9.27%	5
2023 Q2	$109M	Hold	381,282	–	–	8.77%	7
2023 Q1	$106M	Buy	381,282 +1,200	+0.3%	+$332K	8.78%	5
2022 Q4	$105M	Buy	380,082 +19,101	+5%	+$5.39M	8.97%	5
2022 Q3	$96.4M	Hold	360,981	–	–	7.62%	8
2022 Q2	$73.6M	Hold	360,981	–	–	6.42%	7
2022 Q1	$76M	Sell	360,981 -24,019	-6%	-$5.22M	5.88%	8
2021 Q4	$92.4M	Buy	385,000 +23,400	+6%	+$6.02M	5.9%	7
2021 Q3	$102M	Hold	361,600	–	–	6.18%	7
2021 Q2	$125M	Buy	361,600 +18,400	+5%	+$5.57M	6.9%	5
2021 Q1	$96M	Buy	343,200 +108,900	+46%	+$29.4M	5.47%	7
2020 Q4	$57.4M	Buy	+234,300	New	+$60.4M	3.01%	12

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

Palo Alto Investors's BIIB Position: Q1 2026 in Review

Palo Alto Investors reduced its Biogen (BIIB) stake by 23% in Q1 2026, selling an estimated $7.9M and leaving 140,719 shares worth $25.8M. The position accounts for 3.95% of the portfolio, ranked #9.

Palo Alto Investors first reported a position in BIIB in Q4 2020 and has held it in 22 quarters since. The position peaked at $125M in Q2 2021. 1,004 funds tracked by Wall St. Rank hold BIIB as of Q1 2026.

Palo Alto Investors held 140,719 shares of Biogen worth $25.8M as of Q1 2026.
Palo Alto Investors sold 42,852 Biogen shares in Q1 2026, an estimated $7.9M.
Biogen made up 3.95% of Palo Alto Investors's portfolio in Q1 2026, its #9 holding.
Palo Alto Investors first reported a position in Biogen in Q4 2020 and has held it in 22 quarters since.
Palo Alto Investors's Biogen position peaked at $125M in Q2 2021.
1,004 funds tracked by Wall St. Rank held Biogen as of Q1 2026.

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