BIOGEN INC

Ticker: BIIB CUSIP: 09062X103 Class: COM

PUBLIC EMPLOYEES RETIREMENT ASSOCIATION OF COLORADO's Holding History (CIK: 0000315297)

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

Q4 2025

Shares 11,669 Value ($000) $2 Avg Close $163.37 Range $138.00 - $185.17

Q3 2025

Shares 11,669 Value ($000) $2 Avg Close $135.17 Range $121.05 - $150.28

Q2 2025

Shares 11,669 Value ($000) $1 Avg Close $124.60 Range $110.04 - $137.32

Q1 2025

Shares 11,669 Value ($000) $2 Avg Close $142.96 Range $128.51 - $157.09

Q4 2024

Shares 19,043 Value ($000) $3 Avg Close $168.67 Range $145.07 - $195.00

Q3 2024

Shares 20,082 Value ($000) $4 Avg Close $209.21 Range $188.78 - $238.00

Q2 2024

Shares 20,071 Value ($000) $5 Avg Close $217.32 Range $189.44 - $237.54

Q1 2024

Shares 20,594 Value ($000) $4 Avg Close $234.20 Range $211.02 - $268.30

Q4 2023

Shares 21,450 Value ($000) $6 Avg Close $245.62 Range $220.86 - $269.43

Q3 2023

Shares 22,069 Value ($000) $6 Avg Close $267.47 Range $251.85 - $287.60

Q2 2023

Shares 23,725 Value ($000) $7 Avg Close $297.86 Range $273.39 - $319.76

Q1 2023

Shares 23,917 Value ($000) $7 Avg Close $276.70 Range $254.80 - $295.90

Q4 2022

Shares 24,031 Value ($000) $7 Avg Close $282.44 Range $250.31 - $311.88

Q3 2022

Shares 24,140 Value ($000) $6,445 Avg Close $212.38 Range $193.65 - $283.44

Q2 2022

Shares 24,183 Value ($000) $4,932 Avg Close $204.43 Range $187.16 - $225.50

Q1 2022

Shares 24,288 Value ($000) $5,115 Avg Close $217.46 Range $192.67 - $249.00

Q4 2021

Shares 26,815 Value ($000) $6,433 Avg Close $257.12 Range $221.72 - $290.76

Q3 2021

Shares 26,996 Value ($000) $7,640 Avg Close $327.75 Range $282.64 - $372.12

Q2 2021

Shares 27,118 Value ($000) $9,390 Avg Close $302.94 Range $257.03 - $468.55

Q1 2021

Shares 27,254 Value ($000) $7,624 Avg Close $269.69 Range $238.40 - $296.38

Q4 2020

Shares 29,054 Value ($000) $7,114 Avg Close $259.08 Range $223.25 - $363.92

Q3 2020

Shares 30,360 Value ($000) $8,613 Avg Close $278.91 Range $261.87 - $312.00

Q2 2020

Shares 32,744 Value ($000) $8,761 Avg Close $300.59 Range $257.60 - $350.24

Q1 2020

Shares 35,504 Value ($000) $11,233 Avg Close $303.47 Range $262.25 - $374.99

Q4 2019

Shares 35,665 Value ($000) $10,583 Avg Close $277.46 Range $219.70 - $318.00

Q3 2019

Shares 36,866 Value ($000) $8,583 Avg Close $232.85 Range $215.78 - $246.99

Q2 2019

Shares 37,083 Value ($000) $8,673 Avg Close $230.90 Range $219.20 - $245.35

Q1 2019

Shares 39,366 Value ($000) $9,305 Avg Close $314.89 Range $216.12 - $344.00

Q4 2018

Shares 37,622 Value ($000) $11,321 Avg Close $319.14 Range $278.46 - $358.41

Q3 2018

Shares 37,706 Value ($000) $13,322 Avg Close $344.30 Range $288.13 - $388.67

Q2 2018

Shares 38,099 Value ($000) $11,058 Avg Close $281.15 Range $249.17 - $310.91

Q1 2018

Shares 38,320 Value ($000) $10,493 Avg Close $310.41 Range $259.76 - $370.57

Q4 2017

Shares 40,349 Value ($000) $12,854 Avg Close $320.80 Range $301.81 - $348.84

Q3 2017

Shares 38,742 Value ($000) $12,131 Avg Close $296.11 Range $269.50 - $330.00

Q2 2017

Shares 41,136 Value ($000) $11,163 Avg Close $264.42 Range $244.28 - $291.90

Q1 2017

Shares 41,411 Value ($000) $11,323 Avg Close $282.75 Range $260.50 - $301.42

Q4 2016

Shares 42,733 Value ($000) $12,118 Avg Close $296.43 Range $268.00 - $329.83

Q3 2016

Shares 44,422 Value ($000) $13,905 Avg Close $296.18 Range $240.07 - $333.65

Q2 2016

Shares 45,943 Value ($000) $11,110 Avg Close $263.54 Range $223.02 - $292.69

Q1 2016

Shares 51,472 Value ($000) $13,399 Avg Close $264.15 Range $242.07 - $301.02

Q4 2015

Shares 51,193 Value ($000) $15,683 Avg Close $287.35 Range $254.00 - $311.65

Q3 2015

Shares 92,474 Value ($000) $26,985 Avg Close $330.23 Range $265.00 - $412.24

Q2 2015

Shares 109,660 Value ($000) $44,296 Avg Close $401.33 Range $368.88 - $432.88

Q1 2015

Shares 112,373 Value ($000) $47,448 Avg Close $394.14 Range $334.40 - $480.18

Q4 2014

Shares 112,947 Value ($000) $38,340 Avg Close $323.51 Range $290.85 - $361.93

Q3 2014

Shares 126,217 Value ($000) $41,754 Avg Close $329.72 Range $298.31 - $349.00

Q2 2014

Shares 127,609 Value ($000) $40,236 Avg Close $300.97 Range $272.02 - $322.25

Q1 2014

Shares 131,543 Value ($000) $40,235 Avg Close $317.43 Range $270.62 - $358.89

Q4 2013

Shares 147,732 Value ($000) $41,328 Avg Close $258.65 Range $221.07 - $298.82

Q3 2013

Shares 149,348 Value ($000) $35,957 Avg Close $223.81 Range $203.55 - $248.95

Q2 2013

Shares 162,382 Value ($000) $34,945 Avg Close $213.68 Range $191.80 - $242.64

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	11,669	$2	$163.37	$138.00 - $185.17
Q3 2025	11,669	$2	$135.17	$121.05 - $150.28
Q2 2025	11,669	$1	$124.60	$110.04 - $137.32
Q1 2025	11,669	$2	$142.96	$128.51 - $157.09
Q4 2024	19,043	$3	$168.67	$145.07 - $195.00
Q3 2024	20,082	$4	$209.21	$188.78 - $238.00
Q2 2024	20,071	$5	$217.32	$189.44 - $237.54
Q1 2024	20,594	$4	$234.20	$211.02 - $268.30
Q4 2023	21,450	$6	$245.62	$220.86 - $269.43
Q3 2023	22,069	$6	$267.47	$251.85 - $287.60
Q2 2023	23,725	$7	$297.86	$273.39 - $319.76
Q1 2023	23,917	$7	$276.70	$254.80 - $295.90
Q4 2022	24,031	$7	$282.44	$250.31 - $311.88
Q3 2022	24,140	$6,445	$212.38	$193.65 - $283.44
Q2 2022	24,183	$4,932	$204.43	$187.16 - $225.50
Q1 2022	24,288	$5,115	$217.46	$192.67 - $249.00
Q4 2021	26,815	$6,433	$257.12	$221.72 - $290.76
Q3 2021	26,996	$7,640	$327.75	$282.64 - $372.12
Q2 2021	27,118	$9,390	$302.94	$257.03 - $468.55
Q1 2021	27,254	$7,624	$269.69	$238.40 - $296.38
Q4 2020	29,054	$7,114	$259.08	$223.25 - $363.92
Q3 2020	30,360	$8,613	$278.91	$261.87 - $312.00
Q2 2020	32,744	$8,761	$300.59	$257.60 - $350.24
Q1 2020	35,504	$11,233	$303.47	$262.25 - $374.99
Q4 2019	35,665	$10,583	$277.46	$219.70 - $318.00
Q3 2019	36,866	$8,583	$232.85	$215.78 - $246.99
Q2 2019	37,083	$8,673	$230.90	$219.20 - $245.35
Q1 2019	39,366	$9,305	$314.89	$216.12 - $344.00
Q4 2018	37,622	$11,321	$319.14	$278.46 - $358.41
Q3 2018	37,706	$13,322	$344.30	$288.13 - $388.67
Q2 2018	38,099	$11,058	$281.15	$249.17 - $310.91
Q1 2018	38,320	$10,493	$310.41	$259.76 - $370.57
Q4 2017	40,349	$12,854	$320.80	$301.81 - $348.84
Q3 2017	38,742	$12,131	$296.11	$269.50 - $330.00
Q2 2017	41,136	$11,163	$264.42	$244.28 - $291.90
Q1 2017	41,411	$11,323	$282.75	$260.50 - $301.42
Q4 2016	42,733	$12,118	$296.43	$268.00 - $329.83
Q3 2016	44,422	$13,905	$296.18	$240.07 - $333.65
Q2 2016	45,943	$11,110	$263.54	$223.02 - $292.69
Q1 2016	51,472	$13,399	$264.15	$242.07 - $301.02
Q4 2015	51,193	$15,683	$287.35	$254.00 - $311.65
Q3 2015	92,474	$26,985	$330.23	$265.00 - $412.24
Q2 2015	109,660	$44,296	$401.33	$368.88 - $432.88
Q1 2015	112,373	$47,448	$394.14	$334.40 - $480.18
Q4 2014	112,947	$38,340	$323.51	$290.85 - $361.93
Q3 2014	126,217	$41,754	$329.72	$298.31 - $349.00
Q2 2014	127,609	$40,236	$300.97	$272.02 - $322.25
Q1 2014	131,543	$40,235	$317.43	$270.62 - $358.89
Q4 2013	147,732	$41,328	$258.65	$221.07 - $298.82
Q3 2013	149,348	$35,957	$223.81	$203.55 - $248.95
Q2 2013	162,382	$34,945	$213.68	$191.80 - $242.64