Michael R. McDonnell - 01 Sep 2021 Form 4 Insider Report for BIOGEN INC. (BIIB)

Role: EVP, Chief Financial Officer
Signature: /s/ Wendell Taylor, attorney-in-fact for Michael R. McDonnell
Issuer symbol: BIIB
Transactions as of: 01 Sep 2021
Net transactions value: +$1,157,796
Form type: 4
Filing time: 03 Sep 2021, 16:08:01 UTC
Next filing: 14 Feb 2022
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	BIIB	Common Stock	Options Exercise	$906,821	+2,681		$338.24	2,681	01 Sep 2021	Direct
transaction	BIIB	Common Stock	Tax liability	$385,932	-1,141	-43%	$338.24	1,540	01 Sep 2021	Direct
transaction	BIIB	Common Stock	Options Exercise	$1,124,310	+3,324	+216%	$338.24	4,864	01 Sep 2021	Direct
transaction	BIIB	Common Stock	Tax liability	$487,404	-1,441	-30%	$338.24	3,423	01 Sep 2021	Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	BIIB	Restricted Stock Unit	Options Exercise	$0	-2,681	-33%	$0.000000	5,364	01 Sep 2021	Common Stock	2,681	$0.000000	Direct	F1
transaction	BIIB	Restricted Stock Unit	Options Exercise	$0	-3,324	-21%	$0.000000	12,766	01 Sep 2021	Common Stock	3,324	$0.000000	Direct	F2
transaction	BIIB	Restricted Stock Unit	Other	$0	-2,038	-16%	$0.000000	10,728	01 Sep 2021	Common Stock	2,038	$0.000000	Direct	F2, F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The restricted stock units vest in three (3) equal annual installments commencing one year after the grant date of 09/01/2020.
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 average closing stock price for the 30 calendar days following and including the grant date and 30 calendar days prior to and including such vesting date]).
F3	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]).