BIOGEN INC. — Director's Dealing 2011

Feb 25, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2011-02-23

Reporting Person: SCHNEIER CRAIG ERIC (EVP, HR, Public Affairs & Comm)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-02-23	Common Stock	M	4077	—	Acquired	20513.2794	Direct
2011-02-23	Common Stock	M	953	—	Acquired	21466.2794	Direct
2011-02-23	Common Stock	F	1295	$66.76	Disposed	20171.2794	Direct
2011-02-23	Common Stock	F	303	$66.76	Disposed	19868.2794	Direct
2011-02-25	Common Stock	M	9725	$49.31	Acquired	29593.2794	Direct
2011-02-25	Common Stock	S	9725	$68.20	Disposed	19868.2794	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-02-23	Restricted Stock Unit	$0	M	4077	Disposed	2014-02-23	Common Stock (4077)	Direct
2011-02-23	Restricted Stock Unit	$0	M	953	Disposed	2014-02-23	Common Stock (953)	Direct
2011-02-23	Restricted Stock Unit	$0	J	1086	Disposed	2014-02-23	Common Stock (0)	Direct
2011-02-25	Stock Option (Right to Buy)	$49.31	M	9725	Disposed	2017-02-11	Common Stock (9725)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	460	Indirect

Footnotes

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

F2: There is no conversion or exercise price for this stock unit.

F3: 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]).

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

F5: Granted under one of the Issuer's stock option plans, in an exempt transaction under SEC rule 16(b)-3(d).

F6: The stock option becomes exercisable in four (4) equal annual installments, commencing one year after the grant date of 02/12/07.