Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
ALEXANDER SUSAN H
   2. Issuer Name and Ticker or Trading Symbol
BIOGEN INC. [BIIB] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP, Chief Legal Officer
(Last)
(First)
(Middle)
BIOGEN INC., 225 BINNEY STREET		 3. Date of Earliest Transaction (Month/Day/Year)
02/28/2017
(Street)

CAMBRIDGE, MA 02142		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 02/28/2017(1)   M   728 A $ 0 32,568 D  
Common Stock 02/28/2017(1)   F   335 D $ 284.75 32,233 D  
Common Stock 02/28/2017(2)   M   1,375 A $ 0 33,608 D  
Common Stock 02/28/2017(2)   F   447 D $ 287.63 33,161 D  
Common Stock 02/28/2017(3)   M   1,259 A $ 0 34,420 D  
Common Stock 02/28/2017(3)   F   593 D $ 274.76 33,827 D  
Common Stock 02/28/2017(3)   M   2,197 A $ 0 36,024 D  
Common Stock 02/28/2017(3)   F   1,034 D $ 274.76 34,990 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Restricted Stock Unit $ 0 02/28/2017   J     1,477 (4)   (5) 02/12/2017 Common Stock 1,477 $ 0 1,259 D  
Restricted Stock Unit $ 0 02/28/2017   J     1,103 (4)   (6) 02/22/2019 Common Stock 1,103 $ 0 6,335 D  
Restricted Stock Unit $ 0 02/28/2017   J     1,216 (4)   (5) 02/23/2018 Common Stock 1,216 $ 0 2,676 D  
Restricted Stock Unit $ 0 02/28/2017(1)   M     728 (7)   (5) 02/23/2018 Common Stock 728 (7) $ 0 1,948 (7) D  
Restricted Stock Unit $ 0 02/28/2017(2)   M     1,375 (8)   (6) 02/22/2019 Common Stock 1,375 (8) $ 0 4,960 (8) D  
Restricted Stock Unit $ 0 02/28/2017(3)   M     1,259 (9)   (5) 02/12/2017 Common Stock 1,259 (9) $ 0 0 (9) D  
Restricted Stock Unit $ 0 02/28/2017(3)   M     2,197 (10)   (11) 02/12/2017 Common Stock 2,197 (10) $ 0 1 (10) D  
Restricted Stock Unit $ 0 02/28/2017   J     1   (11) 02/12/2017 Common Stock 1 $ 0 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ALEXANDER SUSAN H
BIOGEN INC.
225 BINNEY STREET
CAMBRIDGE, MA 02142		       EVP, Chief Legal Officer  

Signatures

 Steven Avruch, Attorney in Fact for Susan H. Alexander   03/02/2017
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) 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.
(2) 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.
(3) 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.
(4) This represents the difference between the maximum possible number of shares that were eligible for vesting and the actual number that vested.
(5) 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]).
(6) 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]).
(7) This award was previously reported as covering 3,802 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.
(8) This award was previously reported as covering 7,270 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.
(9) This award was previously reported as covering 2,674 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.
(10) This award was previously reported as covering 2,147 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.
(11) 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]).

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