BIOGEN INC. — Director's Dealing 2018

Feb 27, 2018

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2018-02-23

Reporting Person: Sandrock Alfred (EVP, Chief Medical Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2018-02-23	Common Stock	S	908	$293.44	Disposed	6553.3821	Direct
2018-02-23	Common Stock	M	467	—	Acquired	7020.3821	Direct
2018-02-23	Common Stock	F	208	$292.78	Disposed	6812.3821	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2018-02-23	Restricted Stock Unit	$0	M	467	Disposed	2018-02-23	Common Stock (467)	Direct
2018-02-23	Restricted Stock Unit	$0	J	595	Disposed	2018-02-23	Common Stock (595)	Direct

Footnotes

F1: Sale pursuant to a trading plan intended to comply with Rule 10b5-1 of the Securities Exchange Act of 1934.

F2: Full information regarding the number of shares sold at each separate price will be provided upon request by the SEC staff, the issuer, or a security holder of the issuer.

F3: This represents the weighted average price for shares sold at a range between $293.30 (low) and $294.00 (high).

F4: 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]).

F5: This represents the difference between the maximum possible number of shares that were eligible for vesting and the actual number that vested.