BIOGEN INC. — Director's Dealing 2016

Apr 5, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2016-04-02

Reporting Person: Artavanis-Tsakonas Spyridon (EVP, Chief Scientific Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-04-02	Common Stock	M	975	—	Acquired	3608.9671	Direct
2016-04-02	Common Stock	F	459	$260.54	Disposed	3149.9671	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2016-04-02	Restricted Stock Unit	$0	M	975	Disposed	2016-04-02	Common Stock (975)	Direct

Footnotes

F1: Includes 84.8551 shares acquired under the Biogen Inc. employee stock purchase plan on 3/31/2016.

F2: 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]).