Thompson Siegel & Walmsley’s Biogen BIIB Stock Holding History

Thompson Siegel & Walmsley’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	$28.2M	Sell	130,512 -117,831	-47%	-$22.5M	0.51%	68
2026 Q1	$45.5M	Buy	248,343 +19,536	+9%	+$3.6M	0.8%	45
2025 Q4	$40.3M	Sell	228,807 -77,635	-25%	-$12.7M	0.68%	54
2025 Q3	$42.9M	Sell	306,442 -16,576	-5%	-$2.24M	0.69%	56
2025 Q2	$40.6M	Buy	323,018 +65,562	+25%	+$8.17M	0.67%	60
2025 Q1	$35.2M	Buy	+257,456	New	+$36.8M	0.59%	62
2024 Q1	–	Sell	-393	Closed	-$102K	–	376
2023 Q4	$102K	Hold	393	–	–	﹤0.01%	377
2023 Q3	$101K	Hold	393	–	–	﹤0.01%	383
2023 Q2	$112K	Sell	393 -48	-11%	-$14.3K	﹤0.01%	387
2023 Q1	$123K	Hold	441	–	–	﹤0.01%	383
2022 Q4	$122K	Hold	441	–	–	﹤0.01%	372
2022 Q3	$118K	Hold	441	–	–	﹤0.01%	379
2022 Q2	$90K	Hold	441	–	–	﹤0.01%	388
2022 Q1	$93K	Hold	441	–	–	﹤0.01%	426
2021 Q4	$106K	Sell	441 -5	-1%	-$1.29K	﹤0.01%	418
2021 Q3	$126K	Hold	446	–	–	﹤0.01%	401
2021 Q2	$154K	Sell	446 -15	-3%	-$4.54K	﹤0.01%	392
2021 Q1	$129K	Sell	461 -62	-12%	-$16.7K	﹤0.01%	379
2020 Q4	$128K	Sell	523 -15,155	-97%	-$3.91M	﹤0.01%	361
2020 Q3	$4.45M	Sell	15,678 -1,816	-10%	-$507K	0.09%	168
2020 Q2	$4.68M	Buy	17,494 +2,674	+18%	+$804K	0.09%	161
2020 Q1	$4.69M	Buy	14,820 +14,412	+3,532%	+$4.37M	0.11%	146
2019 Q4	$121K	Buy	408 +12	+3%	+$3.33K	﹤0.01%	415
2019 Q3	$92K	Hold	396	–	–	﹤0.01%	450
2019 Q2	$93K	Hold	396	–	–	﹤0.01%	443
2019 Q1	$94K	Hold	396	–	–	﹤0.01%	438
2018 Q4	$119K	Hold	396	–	–	﹤0.01%	405
2018 Q3	$140K	Hold	396	–	–	﹤0.01%	428
2018 Q2	$115K	Hold	396	–	–	﹤0.01%	452
2018 Q1	$108K	Sell	396 -132	-25%	-$41K	﹤0.01%	452
2017 Q4	$168K	Hold	528	–	–	﹤0.01%	430
2017 Q3	$165K	Hold	528	–	–	﹤0.01%	425
2017 Q2	$143K	Buy	528 +132	+33%	+$34.9K	﹤0.01%	444
2017 Q1	$108K	Sell	396 -12	-3%	-$3.39K	﹤0.01%	495
2016 Q4	$116K	Buy	408 +12	+3%	+$3.56K	﹤0.01%	444
2016 Q3	$124K	Hold	396	–	–	﹤0.01%	431
2016 Q2	$96K	Hold	396	–	–	﹤0.01%	424
2016 Q1	$103K	Hold	396	–	–	﹤0.01%	410
2015 Q4	$121K	Hold	396	–	–	﹤0.01%	403
2015 Q3	$116K	Hold	396	–	–	﹤0.01%	411
2015 Q2	$160K	Hold	396	–	–	﹤0.01%	394
2015 Q1	$167K	Hold	396	–	–	﹤0.01%	399
2014 Q4	$134K	Hold	396	–	–	﹤0.01%	410
2014 Q3	$131K	Hold	396	–	–	﹤0.01%	405
2014 Q2	$125K	Hold	396	–	–	﹤0.01%	407
2014 Q1	$121K	Hold	396	–	–	﹤0.01%	412
2013 Q4	$111K	Hold	396	–	–	﹤0.01%	414
2013 Q3	$95K	Hold	396	–	–	﹤0.01%	429
2013 Q2	$85K	Buy	+396	New	+$84.6K	﹤0.01%	434

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

Thompson Siegel & Walmsley's BIIB Position: Q2 2026 in Review

Thompson Siegel & Walmsley reduced its Biogen (BIIB) stake by 47% in Q2 2026, selling an estimated $22.5M and leaving 130,512 shares worth $28.2M. The position accounts for 0.51% of the portfolio, ranked #68.

Thompson Siegel & Walmsley first reported a position in BIIB in Q2 2013 and has held it in 49 quarters since. The position peaked at $45.5M in Q1 2026. 1,036 funds tracked by Wall St. Rank hold BIIB as of Q2 2026.

Thompson Siegel & Walmsley held 130,512 shares of Biogen worth $28.2M as of Q2 2026.
Thompson Siegel & Walmsley sold 117,831 Biogen shares in Q2 2026, an estimated $22.5M.
Biogen made up 0.51% of Thompson Siegel & Walmsley's portfolio in Q2 2026, its #68 holding.
Thompson Siegel & Walmsley first reported a position in Biogen in Q2 2013 and has held it in 49 quarters since.
Thompson Siegel & Walmsley's Biogen position peaked at $45.5M in Q1 2026.
1,036 funds tracked by Wall St. Rank held Biogen as of Q2 2026.

Based on Thompson Siegel & Walmsley's 13F filing for Q2 2026, filed 11 Aug 2026.