BIOGEN INC. — Director's Dealing 2017

Mar 2, 2017

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2017-02-28

Reporting Person: Clancy Paul J (Executive VP and CFO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2017-02-28	Common Stock	M	663	—	Acquired	27533	Direct
2017-02-28	Common Stock	F	312	$284.75	Disposed	27221	Direct
2017-02-28	Common Stock	M	2092	—	Acquired	29313	Direct
2017-02-28	Common Stock	F	847	$287.63	Disposed	28466	Direct
2017-02-28	Common Stock	M	1152	—	Acquired	29618	Direct
2017-02-28	Common Stock	F	543	$274.76	Disposed	29075	Direct
2017-02-28	Common Stock	M	2873	—	Acquired	31948	Direct
2017-02-28	Common Stock	F	1352	$274.76	Disposed	30596	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2017-02-28	Restricted Stock Unit	$0	J	1352	Disposed	2017-02-12	Common Stock (1352)	Direct
2017-02-28	Restricted Stock Unit	$0	J	1678	Disposed	2019-02-22	Common Stock (1678)	Direct
2017-02-28	Restricted Stock Unit	$0	J	1105	Disposed	2018-02-23	Common Stock (1105)	Direct
2017-02-28	Restricted Stock Unit	$0	M	663	Disposed	2018-02-23	Common Stock (663)	Direct
2017-02-28	Restricted Stock Unit	$0	M	2092	Disposed	2019-02-22	Common Stock (2092)	Direct
2017-02-28	Restricted Stock Unit	$0	M	1152	Disposed	2017-02-12	Common Stock (1152)	Direct
2017-02-28	Restricted Stock Unit	$0	M	2873	Disposed	2017-02-12	Common Stock (2873)	Direct

Footnotes

F1: This award vested on 2/23/2017 and the actual number of shares that vested was determined in accordance with the terms of such award. Due to adjustments to the award to account for the Bioverativ Inc. spin-off, the number of vested shares was not determinable until 2/28/2017. Such adjusted number of vested shares was distributed to the reporting person on 2/28/2017.

F2: This award vested on 2/22/2017 and the actual number of shares that vested was determined in accordance with the terms of such award. Due to adjustments to the award to account for the Bioverativ Inc. spin-off, the number of vested shares was not determinable until 2/28/2017. Such adjusted number of vested shares was distributed to the reporting person on 2/28/2017.

F3: This award vested on 2/12/2017 and the actual number of shares that vested was determined in accordance with the terms of such award. Due to adjustments to the award to account for the Bioverativ Inc. spin-off, the number of vested shares was not determinable until 2/28/2017. Such adjusted number of vested shares was distributed to the reporting person on 2/28/2017.

F4: This represents the difference between the maximum possible number of shares that were eligible for vesting and the actual number that vested.

F5: 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]).

F6: 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]).

F7: This award was previously reported as covering 3,462 shares, but was adjusted pursuant to the anti-dilution provisions of the award in connection with the spin-off of Bioverativ Inc. on February 1, 2017.

F8: This award was previously reported as covering 11,060 shares, but was adjusted pursuant to the anti-dilution provisions of the award in connection with the spin-off of Bioverativ Inc. on February 1, 2017.

F9: This award was previously reported as covering 2,448 shares, but was adjusted pursuant to the anti-dilution provisions of the award in connection with the spin-off of Bioverativ Inc. on February 1, 2017.

F10: This award was previously reported as covering 2,808 shares, but was adjusted pursuant to the anti-dilution provisions of the award in connection with the spin-off of Bioverativ Inc. on February 1, 2017.

F11: 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]).