BIOGEN INC

Ticker: BIIB CUSIP: 09062X103 Class: COM

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC's Holding History (CIK: 0001644956)

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

Q4 2018
Shares 28,149 Value ($000) $8,470 Avg Close $319.14 Range $278.46 - $358.41
Q3 2018
Shares 67,618 Value ($000) $23,890 Avg Close $344.30 Range $288.13 - $388.67
Q2 2018
Shares 114,696 Value ($000) $33,289 Avg Close $281.15 Range $249.17 - $310.91
Q1 2018
Shares 118,198 Value ($000) $32,365 Avg Close $310.41 Range $259.76 - $370.57
Q4 2017
Shares 146,625 Value ($000) $46,710 Avg Close $320.80 Range $301.81 - $348.84
Q3 2017
Shares 151,336 Value ($000) $47,386 Avg Close $296.11 Range $269.50 - $330.00
Q2 2017
Shares 205,107 Value ($000) $55,658 Avg Close $264.42 Range $244.28 - $291.90
Q1 2017
Shares 293,047 Value ($000) $80,125 Avg Close $282.75 Range $260.50 - $301.42
Q4 2016
Shares 435,849 Value ($000) $123,598 Avg Close $296.43 Range $268.00 - $329.83
Q3 2016
Shares 431,731 Value ($000) $135,145 Avg Close $296.18 Range $240.07 - $333.65
Q2 2016
Shares 364,387 Value ($000) $88,116 Avg Close $263.54 Range $223.02 - $292.69
Q1 2016
Shares 371,446 Value ($000) $96,695 Avg Close $264.15 Range $242.07 - $301.02
Q4 2015
Shares 315,794 Value ($000) $96,743 Avg Close $287.35 Range $254.00 - $311.65
Q3 2015
Shares 242,177 Value ($000) $70,670 Avg Close $330.23 Range $265.00 - $412.24