X0306 4 2016-02-08 0000875045 BIOGEN INC. BIIB 0001300247 Holtzman Steven H BIOGEN INC. 225 BINNEY STREET CAMBRIDGE MA 02142 1 EVP Corporate Development Common Stock 2016-02-08 4 M 0 2709 0 A 7030 D Common Stock 2016-02-08 4 F 0 890 250.77 D 6140 D Restricted Stock Unit 0 2016-02-08 4 M 0 2709 0 D 2016-02-08 Common Stock 2709 0 D The number of RSUs reported represents the maximum possible number of shares that are eligible for vesting, which is 150% of the number of shares at target payout. One-fourth of these RSUs are eligible to vest on each of the first four anniversaries of the grant date. The actual number of shares that will vest on each vesting date will be determined by comparing the price of Biogen Idec common stock on such vesting date to the price on the grant date (i.e., number of vested shares = number of shares at target payout times [the average 60 calendar-day closing stock price ending on the vesting date divided by the average 60 calendar-day closing stock price on the grant date]). Matthew S. Gilman, Attorney-in-Fact for Steven H. Holtzman 2016-02-09