BIOGEN INC. — Director's Dealing 2018

Jan 4, 2018

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2018-01-02

Reporting Person: CAPELLO JEFFREY D (EVP & Chief Financial Officer)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2018-01-02	Restricted Stock Unit	$0	A	8980	Acquired	2021-01-02	Common Stock (8980)	Direct
2018-01-02	Performance Stock Unit	$0	A	5390	Acquired		Common Stock (5390)	Direct

Footnotes

F1: 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 following and including the grant date]).

F2: The number of performance stock units ("PSUs") reported represents the maximum possible number of shares that are eligible for vesting, which is 200% of the number of shares at target payout. The actual number of PSUs that will vest will be determined based upon achievement of three-year performance goals adopted by the Compensation and Management Development Committee of the Board of Directors (the "Committee") in the first quarter of 2018.

F3: All eligible PSUs will vest on the later of January 2, 2021 or the date of the Committee's determination of the degree to which the annual performance goals have been satisfied.