BIOGEN INC. — Director's Dealing 2018

Jan 8, 2018

SEC Form 4/A — Form 4/A

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2017-12-01

Reporting Person: Guindo Chirfi (EVP Glob. Mkt Acc & Cust Innov)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2017-12-01	Restricted Stock Unit	$0	A	3510	Acquired	2020-12-01	Common Stock (3510)	Direct

Footnotes

F1: In the original Form 4, the number of Restricted Stock Units acquired was reported at the target payout and should have been reported at the maximum possible number of shares that are eligible for vesting, which is 200% of the number of shares at target payout.

F2: The number of RSUs reported represents the maximum possible number of shares that are eligible for vesting, which is 200% of the number of shares at target payout. One-third of these RSUs are eligible to vest on each of the first three 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 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 30-day average closing stock price ending on the vesting date divided by the 30-day average closing stock price on the grant date]).