BIOGEN INC. — Director's Dealing 2011

Sep 29, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN IDEC INC. (BIIB)
CIK: 0000875045
Period of Report: 2011-09-27

Reporting Person: YOUNG WILLIAM (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-09-27	Common Stock	M	12500	$47.55	Acquired	39359	Direct
2011-09-27	Common Stock	M	3125	$46.99	Acquired	42484	Direct
2011-09-27	Common Stock	M	5950	$52.22	Acquired	48434	Direct
2011-09-27	Common Stock	M	5700	$59.17	Acquired	54134	Direct
2011-09-27	Common Stock	M	5975	$53.43	Acquired	60109	Direct
2011-09-27	Common Stock	S	33250	$96.14	Disposed	26859	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-09-27	Stock Option (Right to Buy)	$47.55	M	12500	Disposed	2016-01-09	Common Stock (12500)	Direct
2011-09-27	Employee Stock Option (Right to Buy)	$46.99	M	3125	Disposed	2016-05-24	Common Stock (3125)	Direct
2011-09-27	Stock Option (Right to Buy)	$52.22	M	5950	Disposed	2017-05-30	Common Stock (5950)	Direct
2011-09-27	Stock Option (Right to Buy)	$59.17	M	5700	Disposed	2018-06-18	Common Stock (5700)	Direct
2011-09-27	Stock Option (Right to Buy)	$53.43	M	5975	Disposed	2019-06-02	Common Stock (5975)	Direct

Footnotes

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

F2: Granted under one of the Issuer's stock option plans, in an exempt transaction under SEC Rule 16(b)-3(d).

F3: Immediately exercisable for all the option shares on grant date of 01/09/2006 subject to Issuer's repurchase rights which lapse on 01/09/2007.

F4: Options will vest in their entirety on 05/25/2007 provided that the Reporting Owner is then a member of the Issuer's Board of Directors.

F5: Options will become 100% exercisable upon completion of one year of service with Biogen Idec Inc.