BIOGEN INC

Ticker: BIIB CUSIP: 09062X103 Class: COM

BLAIR WILLIAM & CO/IL's Holding History (CIK: 0000902367)

Note: Option positions (PUT/CALL) are excluded.

Q4 2025

Shares 8,443 Value ($000) $1,486 Avg Close $163.37 Range $138.00 - $185.17

Q3 2025

Shares 14,020 Value ($000) $1,964 Avg Close $135.17 Range $121.05 - $150.28

Q2 2025

Shares 14,844 Value ($000) $1,864 Avg Close $124.60 Range $110.04 - $137.32

Q1 2025

Shares 13,283 Value ($000) $1,818 Avg Close $142.96 Range $128.51 - $157.09

Q4 2024

Shares 13,049 Value ($000) $1,996 Avg Close $168.67 Range $145.07 - $195.00

Q3 2024

Shares 12,155 Value ($000) $2,356 Avg Close $209.21 Range $188.78 - $238.00

Q2 2024

Shares 13,094 Value ($000) $3,035 Avg Close $217.32 Range $189.44 - $237.54

Q1 2024

Shares 12,867 Value ($000) $2,775 Avg Close $234.20 Range $211.02 - $268.30

Q4 2023

Shares 11,735 Value ($000) $3,037 Avg Close $245.62 Range $220.86 - $269.43

Q3 2023

Shares 14,123 Value ($000) $3,630 Avg Close $267.47 Range $251.85 - $287.60

Q2 2023

Shares 10,555 Value ($000) $3,007 Avg Close $297.86 Range $273.39 - $319.76

Q1 2023

Shares 10,912 Value ($000) $3,034 Avg Close $276.70 Range $254.80 - $295.90

Q4 2022

Shares 10,332 Value ($000) $2,861 Avg Close $282.44 Range $250.31 - $311.88

Q3 2022

Shares 12,488 Value ($000) $3,334 Avg Close $212.38 Range $193.65 - $283.44

Q2 2022

Shares 14,014 Value ($000) $2,858 Avg Close $204.43 Range $187.16 - $225.50

Q1 2022

Shares 14,526 Value ($000) $3,059 Avg Close $217.46 Range $192.67 - $249.00

Q4 2021

Shares 17,762 Value ($000) $4,261 Avg Close $257.12 Range $221.72 - $290.76

Q3 2021

Shares 13,685 Value ($000) $3,873 Avg Close $327.75 Range $282.64 - $372.12

Q2 2021

Shares 11,388 Value ($000) $3,943 Avg Close $302.94 Range $257.03 - $468.55

Q1 2021

Shares 10,316 Value ($000) $2,886 Avg Close $269.69 Range $238.40 - $296.38

Q4 2020

Shares 9,972 Value ($000) $2,442 Avg Close $259.08 Range $223.25 - $363.92

Q3 2020

Shares 10,384 Value ($000) $2,946 Avg Close $278.91 Range $261.87 - $312.00

Q2 2020

Shares 9,346 Value ($000) $2,501 Avg Close $300.59 Range $257.60 - $350.24

Q1 2020

Shares 9,402 Value ($000) $2,975 Avg Close $303.47 Range $262.25 - $374.99

Q4 2019

Shares 11,891 Value ($000) $3,528 Avg Close $277.46 Range $219.70 - $318.00

Q2 2019

Shares 10,244 Value ($000) $0 Avg Close $230.90 Range $219.20 - $245.35

Q1 2019

Shares 15,218 Value ($000) $3,597 Avg Close $314.89 Range $216.12 - $344.00

Q4 2018

Shares 16,655 Value ($000) $5,012 Avg Close $319.14 Range $278.46 - $358.41

Q3 2018

Shares 18,449 Value ($000) $6,518 Avg Close $344.30 Range $288.13 - $388.67

Q2 2018

Shares 15,714 Value ($000) $4,561 Avg Close $281.15 Range $249.17 - $310.91

Q1 2018

Shares 24,037 Value ($000) $6,582 Avg Close $310.41 Range $259.76 - $370.57

Q4 2017

Shares 25,099 Value ($000) $7,996 Avg Close $320.80 Range $301.81 - $348.84

Q3 2017

Shares 24,053 Value ($000) $7,531 Avg Close $296.11 Range $269.50 - $330.00

Q2 2017

Shares 14,713 Value ($000) $3,993 Avg Close $264.42 Range $244.28 - $291.90

Q1 2017

Shares 15,898 Value ($000) $4,505 Avg Close $282.75 Range $260.50 - $301.42

Q4 2016

Shares 24,123 Value ($000) $6,841 Avg Close $296.43 Range $268.00 - $329.83

Q3 2016

Shares 23,740 Value ($000) $7,431 Avg Close $296.18 Range $240.07 - $333.65

Q2 2016

Shares 23,542 Value ($000) $5,693 Avg Close $263.54 Range $223.02 - $292.69

Q1 2016

Shares 39,072 Value ($000) $10,171 Avg Close $264.15 Range $242.07 - $301.02

Q4 2015

Shares 37,495 Value ($000) $11,486 Avg Close $287.35 Range $254.00 - $311.65

Q3 2015

Shares 83,133 Value ($000) $24,259 Avg Close $330.23 Range $265.00 - $412.24

Q2 2015

Shares 33,497 Value ($000) $13,531 Avg Close $401.33 Range $368.88 - $432.88

Q1 2015

Shares 25,978 Value ($000) $10,968 Avg Close $394.14 Range $334.40 - $480.18

Q4 2014

Shares 17,129 Value ($000) $5,814 Avg Close $323.51 Range $290.85 - $361.93

Q3 2014

Shares 10,217 Value ($000) $3,380 Avg Close $329.72 Range $298.31 - $349.00

Q2 2014

Shares 9,350 Value ($000) $2,948 Avg Close $300.97 Range $272.02 - $322.25

Q1 2014

Shares 34,573 Value ($000) $10,574 Avg Close $317.43 Range $270.62 - $358.89

Q4 2013

Shares 31,599 Value ($000) $8,839 Avg Close $258.65 Range $221.07 - $298.82

Q3 2013

Shares 20,708 Value ($000) $4,985 Avg Close $223.81 Range $203.55 - $248.95

Q2 2013

Shares 20,341 Value ($000) $4,377 Avg Close $213.68 Range $191.80 - $242.64

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	8,443	$1,486	$163.37	$138.00 - $185.17
Q3 2025	14,020	$1,964	$135.17	$121.05 - $150.28
Q2 2025	14,844	$1,864	$124.60	$110.04 - $137.32
Q1 2025	13,283	$1,818	$142.96	$128.51 - $157.09
Q4 2024	13,049	$1,996	$168.67	$145.07 - $195.00
Q3 2024	12,155	$2,356	$209.21	$188.78 - $238.00
Q2 2024	13,094	$3,035	$217.32	$189.44 - $237.54
Q1 2024	12,867	$2,775	$234.20	$211.02 - $268.30
Q4 2023	11,735	$3,037	$245.62	$220.86 - $269.43
Q3 2023	14,123	$3,630	$267.47	$251.85 - $287.60
Q2 2023	10,555	$3,007	$297.86	$273.39 - $319.76
Q1 2023	10,912	$3,034	$276.70	$254.80 - $295.90
Q4 2022	10,332	$2,861	$282.44	$250.31 - $311.88
Q3 2022	12,488	$3,334	$212.38	$193.65 - $283.44
Q2 2022	14,014	$2,858	$204.43	$187.16 - $225.50
Q1 2022	14,526	$3,059	$217.46	$192.67 - $249.00
Q4 2021	17,762	$4,261	$257.12	$221.72 - $290.76
Q3 2021	13,685	$3,873	$327.75	$282.64 - $372.12
Q2 2021	11,388	$3,943	$302.94	$257.03 - $468.55
Q1 2021	10,316	$2,886	$269.69	$238.40 - $296.38
Q4 2020	9,972	$2,442	$259.08	$223.25 - $363.92
Q3 2020	10,384	$2,946	$278.91	$261.87 - $312.00
Q2 2020	9,346	$2,501	$300.59	$257.60 - $350.24
Q1 2020	9,402	$2,975	$303.47	$262.25 - $374.99
Q4 2019	11,891	$3,528	$277.46	$219.70 - $318.00
Q2 2019	10,244	$0	$230.90	$219.20 - $245.35
Q1 2019	15,218	$3,597	$314.89	$216.12 - $344.00
Q4 2018	16,655	$5,012	$319.14	$278.46 - $358.41
Q3 2018	18,449	$6,518	$344.30	$288.13 - $388.67
Q2 2018	15,714	$4,561	$281.15	$249.17 - $310.91
Q1 2018	24,037	$6,582	$310.41	$259.76 - $370.57
Q4 2017	25,099	$7,996	$320.80	$301.81 - $348.84
Q3 2017	24,053	$7,531	$296.11	$269.50 - $330.00
Q2 2017	14,713	$3,993	$264.42	$244.28 - $291.90
Q1 2017	15,898	$4,505	$282.75	$260.50 - $301.42
Q4 2016	24,123	$6,841	$296.43	$268.00 - $329.83
Q3 2016	23,740	$7,431	$296.18	$240.07 - $333.65
Q2 2016	23,542	$5,693	$263.54	$223.02 - $292.69
Q1 2016	39,072	$10,171	$264.15	$242.07 - $301.02
Q4 2015	37,495	$11,486	$287.35	$254.00 - $311.65
Q3 2015	83,133	$24,259	$330.23	$265.00 - $412.24
Q2 2015	33,497	$13,531	$401.33	$368.88 - $432.88
Q1 2015	25,978	$10,968	$394.14	$334.40 - $480.18
Q4 2014	17,129	$5,814	$323.51	$290.85 - $361.93
Q3 2014	10,217	$3,380	$329.72	$298.31 - $349.00
Q2 2014	9,350	$2,948	$300.97	$272.02 - $322.25
Q1 2014	34,573	$10,574	$317.43	$270.62 - $358.89
Q4 2013	31,599	$8,839	$258.65	$221.07 - $298.82
Q3 2013	20,708	$4,985	$223.81	$203.55 - $248.95
Q2 2013	20,341	$4,377	$213.68	$191.80 - $242.64