BIOGEN INC. — Director's Dealing 2018

Feb 20, 2018

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2018-02-15

Reporting Person: Ehlers Michael D (EVP, Research and Development)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2018-02-15	Common Stock	M	1712	—	Acquired	5407.359	Direct
2018-02-15	Common Stock	F	509	$299.38	Disposed	4898.359	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2018-02-15	Restricted Stock Unit	$0	M	1712	Disposed	2020-02-15	Common Stock (1712)	Direct
2018-02-15	Restricted Stock Unit	$0	J	1006	Disposed	2020-02-15	Common Stock (1006)	Direct

Footnotes

F1: Includes 39.569 shares and 39.790 shares acquired under the Biogen Inc. employee stock purchase plan on 9/29/2017 and 12/29/2017, respectively.

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]).

F3: This represents the difference between the maximum possible number of shares that were eligible for vesting and the actual number that vested.