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the anticipated amount, timing and accounting of revenues, contingent payments, milestone, royalty and other payments under licensing, collaboration or acquisition agreements, tax positions and contingencies, doubtful accounts, pre-approval inventory, cost of sales, research and development costs, compensation and other expenses, amortization of intangible assets, and foreign currency forward contracts;

•	the anticipated timing of commercial launches of TECFIDERA in European countries;

•	anticipated regulatory filings and regulatory actions relating to, and commercial launch of, ELOCTATE and ALPROLIX;

•	additional anticipated commercial launches of FAMPYRA and the timing thereof;

•	patent terms, patent term extensions, patent office actions, and expected availability and period of data protection and market exclusivity rights;

•	the potential impact of increased product competition in the multiple sclerosis (MS) market, including competition from and growth of our own products and the possibility of future competition from biosimilars, generic versions or related prodrug derivatives;

•	the potential for increased competition between RITUXAN and GAZYVA in the oncology market;

•	our plans to develop further risk stratification protocols and therapies for TYSABRI and the impact of such protocols;

•	the timing, outcome and impact of administrative, regulatory, litigation and other proceedings related to patents and other proprietary and intellectual property rights, tax audits, assessments and settlements, product liability and other matters;

•	the impact of the commercial launch of TECFIDERA on sales and market share of our products;

•	the expected timing and financial impact of the final approval of the settlement of our dispute with the Italian National Medicines Agency relating to sales of TYSABRI;

•	the anticipated lifetime revenues of AVONEX and TYSABRI and amortization recorded in relation to their technology;

•	the costs, timing, potential approval and therapeutic scope of the development and commercialization of our pipeline products;

•	lease commitments and purchase obligations;

•	the potential impact of budget cuts and other measures in the U.S. and worldwide designed to reduce healthcare costs to constrain the overall level of government expenditures, including the impact of pricing actions in Europe and elsewhere;

•	the impact of the continued uncertainty and deterioration of the credit and economic conditions in certain countries in Europe and our collection of accounts receivable in such countries;

•	our ability to finance our operations and business initiatives and obtain funding for such activities;

•	the impact of new laws and accounting standards;

•	the expected timing of completion of our manufacturing obligation for Zevalin;

•	manufacturing capacity and our intent to utilize third party contract manufacturing organizations to provide manufacturing services for our small molecule products; and

•	the drivers for growing our business, including our plans to pursue business development and research opportunities, and competitive conditions.

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Item 1.	Business

(1)	AVONEX (interferon beta-1a), injection for intramuscular use, is indicated for the treatment of patients with relapsing forms of MS to slow the accumulation of physical disability and decrease the frequency of clinical exacerbations.

(2)

TYSABRI (natalizumab), injection for intravenous infusion, is indicated (1) as a monotherapy for the treatment of patients with relapsing forms of MS to delay the accumulation of physical disability and reduce the frequency of clinical exacerbations and (2) in the U.S. for inducing and maintaining clinical response and remission in adult patients with moderately to severely active Crohn's disease with evidence of inflammation who have had an inadequate response to, or are unable to tolerate, conventional Crohn's disease therapies and TNF inhibitors.

(3)

TECFIDERA (dimethyl fumarate), delayed release capsules for oral use, is indicated for the treatment of patients with relapsing forms of MS. TECFIDERA was approved by the U.S. Food and Drug Administration (FDA) in March 2013. In February 2014, the European Commission (EC) approved the use of TECFIDERA in the European Union (E.U.) as a first-line oral treatment for people with relapsing-remitting MS.

(4)	FAMPYRA (prolonged-release fampridine tablets) is indicated for the improvement of walking ability in adult patients with MS who have walking disability.

(5)	FUMADERM (fumaric acid esters), prolonged release tablets, is only approved in Germany and is indicated for the treatment of adult patients with moderate to severe plaque psoriasis for whom topical therapy is ineffective.

(6)

RITUXAN (rituximab), injection for intravenous infusion, is indicated for the treatment of (1)(a) relapsed or refractory, low-grade or follicular, CD20-positive, B-cell Non-Hodgkin's lymphoma (NHL) as a single agent, (b) previously untreated follicular, CD20-positive, B-cell NHL in combination with first line chemotherapy and, in patients achieving a complete or partial response to RITUXAN in combination with chemotherapy, as a single-agent maintenance therapy, (c) non-progressing (including stable disease), low-grade, CD20-positive, B-cell NHL, as a single agent, after first-line CVP chemotherapy, and (d) previously untreated diffuse large B-cell, CD20-positive NHL in combination with CHOP or

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We previously collaborated with Elan on the development, manufacture and commercialization of TYSABRI. On April 2, 2013, we acquired full ownership of, and strategic, commercial and decision-making rights to, TYSABRI from Elan, for an upfront payment of $3.25 billion together with an agreement to make contingent payments to Elan. Upon the closing of the transaction, our collaboration agreement with Elan was terminated. For additional information related to this relationship, please read Note 2, Acquisitions and Note 20, Collaborative and Other Relationships to our consolidated financial statements included within this report.

•

In 2013, the FDA and the European Medicines Agency (EMA) approved updates to the TYSABRI product labels. In July 2013, the EMA approved an expanded indication statement for TYSABRI to include glatiramer acetate (GA) treatment failures in the definition of non-responders eligible for TYSABRI, and in December 2013, the FDA approved a modification to the indication statement in the U.S. product label for TYSABRI clarifying the intended use of TYSABRI for people living with relapsing forms of MS, as well as updates to certain safety information. In May 2013, we withdrew the variation in our application we submitted to the EMA requesting to expand the indication statement to allow first-line use of TYSABRI for people living with certain relapsing forms of MS who have tested negative for antibodies to the JC virus.

•	In 2013, we submitted an application for approval of TYSABRI in Japan.

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The EC granted a conditional marketing authorization for FAMPYRA in the E.U. in July 2011. A conditional marketing authorization is renewable annually and is granted to a medicinal product with a positive benefit-risk assessment that fulfills an unmet medical need when the benefit to public health of immediate availability outweighs the risk inherent in the fact that additional data are still required. This marketing authorization was renewed as of July 2013. To meet the conditions of this marketing authorization, we will continue to provide additional data from on-going clinical studies regarding FAMPYRA's benefits and safety.

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•	GOYA: investigating the efficacy and safety of GAZYVA in combination with CHOP chemotherapy compared to RITUXAN with CHOP chemotherapy in previously untreated patients with CD20-positive diffuse large B-cell lymphoma.

•	GALLIUM: investigating the efficacy and safety of GAZYVA in combination with chemotherapy followed by maintenance with GAZYVA compared to RITUXAN in combination with chemotherapy followed by maintenance with RITUXAN in previously untreated patients with indolent non-Hodgkin's lymphoma.

•	GADOLIN: investigating the efficacy and safety of GAZYVA plus bendamustine compared with bendamustine alone in patients with RITUXAN-refractory, indolent non-Hodgkin's lymphoma.

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•	U.S. patent no. 6,509,376, having claims to formulations of dimethyl fumarate for use in the treatment of autoimmune diseases including MS, expiring in 2019;

•	U.S. patent no. 7,320,999, having claims to a method of treating MS using dimethyl fumarate, expiring in 2020;

•	U.S. patent no. 7,619,001, having claims to a method of treating MS using dimethyl fumarate, monomethyl fumarate, or a combination thereof, expiring in 2018;

•	U.S. patent no. 7,803,840, having claims to a method of treating an autoimmune disease selected from autoimmune polyarthritis and MS using dimethyl fumarate, expiring in 2018;

•	U.S. patent no. 8,399,514, covering the dosing regimen of 240 mg of TECFIDERA administered twice a day, expiring in 2028; and

•	U.S. patent no. 8,524,773, having claims to a method of treating MS using monomethyl fumarate, expiring in 2018.

•	EP 1131065, directed to formulations of dimethyl fumarate and to uses thereof for treating autoimmune diseases, including MS, expiring in 2019; and

•	EP 2137537, the counterpart patent to our U.S. patent covering the dosing regimen of 240 mg of TECFIDERA administered twice a day, expiring in 2028.

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•	COPAXONE (glatiramer acetate), which is marketed by Teva Pharmaceutical Industries Ltd. COPAXONE generated worldwide revenues of approximately $4.0 billion in 2012.

•	REBIF (interferon-beta-1a), which is marketed by Merck (and co-promoted with Pfizer Inc. in the U.S.). REBIF generated worldwide revenues of approximately $2.5 billion in 2012.

•	BETASERON/BETAFERON (interferon-beta-1b), which is marketed by the Bayer Group. BETASERON/BETAFERON generated worldwide revenues of approximately $1.6 billion in 2012.

•	EXTAVIA (interferon-beta-1b), which is marketed by Novartis AG. EXTAVIA generated worldwide revenues of approximately $159.0 million in 2012.

•	GILENYA (fingolimod), which is marketed by Novartis AG. GILENYA generated worldwide revenues of approximately $1.2 billion in 2012.

•	AUBAGIO (teriflunomide), which is marketed by Sanofi. AUBAGIO generated worldwide revenues of approximately $9.2 million in 2012.

•	TREANDA (bendamustine HCL) (marketed by Cephalon (Teva Pharmaceuticals)), which is indicated for CLL and for patients with indolent B-cell NHL that has progressed within 6 months of treatment with RITUXAN.

•	ARZERRA (ofatumumab) (marketed by GenMab in collaboration with GlaxoSmithKline), which is indicated for CLL patients refractory to both alemtuzumab and fludarabine.

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•	Traditional therapies for RA, including disease-modifying anti-rheumatic drugs such as steroids, methotrexate and cyclosporine, and pain relievers such as acetaminophen.

•	TNF inhibitors, such as REMICADE (infliximab) and SIMPONI and SIMPONI ARIA (golimumab) (marketed by Johnson & Johnson), HUMIRA (adalimumab) (marketed by AbbVie, Inc.), ENBREL (etanercept) (marketed by Amgen, Inc. and Pfizer) and CIMZIA (certolizumab pegol) (marketed by UCB, S.A.).

•	ORENCIA (abatacept) (marketed by Bristol-Myers Squibb Company).

•	ACTEMRA (tocilizumab) (marketed by the Roche Group).

•	XELJANZ (tofacitinib) (marketed by Pfizer).

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Item  1A.	Risk Factors

•	intense competition in the increasingly crowded MS market, including the possibility of future competition from generic versions of TECFIDERA or related prodrug derivatives or from off-label use by physicians of therapies indicated for other conditions to treat MS patients;

•	our significant reliance on third parties to manufacture TECFIDERA, including the risks these third parties may not be able to supply TECFIDERA in a timely and cost-effective manner or in compliance with applicable regulations or otherwise fail to have sufficient aggregate manufacturing capacity to satisfy demand;

•	our sales and marketing efforts may not result in product revenues that meet the investment community's expectations for TECFIDERA;

•

additional risks associated with our anticipated launches of TECFIDERA in the E.U., including the impact of delays and the effects of a slower rollout of TECFIDERA across European countries over an extended number of months, the impact of competitive oral MS therapies approved in the E.U. prior to TECFIDERA, and our ability to obtain appropriate pricing and reimbursement for TECFIDERA in countries throughout the E.U.;

•	damage to our sales and reputation, and physician and patient confidence in TECFIDERA relating to any adverse experiences or events that may occur with patients treated with TECFIDERA, including any PML cases that may develop in patients previously treated with TYSABRI that switch to therapy with TECFIDERA; and

•	the other risks related to commercialization of new products described throughout these “Risk Factors”.

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•	the medical community's acceptance of the product and the confidence of patients in the product;

•	the effectiveness of our sales force and marketing efforts;

•	the size of the patient population and our ability to identify new patients;

•	pricing and the extent of reimbursement from third party payors;

•	the ability to obtain and maintain data or market exclusivity for our products in the relevant indication(s);

•	our ability to offer products that have convenient dosing and delivery methods;

•	the availability or introduction of competing treatments that are deemed more effective, safer, more convenient, or less expensive;

•	manufacturing the product in a timely and cost-effective manner; and

•	compliance with complex regulatory requirements.

•	the hemophilia treatment market is highly competitive, with current treatments marketed by companies that have substantially greater financial resources and marketing expertise, and we may have difficulty penetrating this highly competitive market unless our long-lasting blood clotting factor candidates are regarded as offering substantial benefits over current treatments;

•	we do not have marketing experience within the hemophilia treatment market or well-established relationships with the associated medical and scientific community;

•	filing of our planned marketing authorization applications with the EMA requires the submission of positive pediatric data from our ongoing global pediatric studies with our applications, and there can be no assurance that we will receive such positive data; and

•	several companies are working to develop additional treatments for hemophilia and may obtain marketing approval of their treatments before we do, which has the potential to bar our application with the EMA under operation of the EMA’s Orphan Medicines Regulation; and

•	other companies may introduce longer-lasting or more efficacious, safer, cheaper or more convenient treatments than our long-lasting blood clotting factor candidates.

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•	Our RITUXAN revenues, as well as any future revenues related to GAZYVA, are dependent on the efforts of Genentech and the Roche Group. Their interests may not always be aligned with our interests and they may not market RITUXAN or GAZYVA in the same manner or to the same extent that we would, which could adversely affect our RITUXAN or GAZYVA revenues.

•	Under our collaboration agreement with Genentech, the successful development and commercialization of GAZYVA and certain other anti-CD20 products will decrease our percentage of the collaboration's co-promotion profits.

•

Any failure on the part of our collaborators to comply with applicable laws and regulatory requirements in the sale, marketing and maintenance of the market authorization of our products or to fulfill any responsibilities they may have to protect and enforce any intellectual property rights underlying our products could have an adverse effect on our revenues as well as involve us in possible legal proceedings.

•	Collaborations often require the parties to cooperate, and failure to do so effectively could have an adverse impact on product sales by our collaborators, and could adversely affect the clinical development or regulatory approvals of products under joint control.

•

The process of manufacturing biologics is extremely susceptible to product loss due to contamination, oxidation, equipment failure or improper installation or operation of equipment, or vendor or operator error. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects and other supply disruptions. If microbial, viral or other contaminations are discovered in our products or manufacturing facilities, we may need to close our manufacturing facilities for an extended period of time to investigate and remediate the contaminant.

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We rely on third party suppliers and manufacturers for, among other things, manufacturing of RITUXAN and GAZYVA, the majority of our clinical and commercial requirements for TECFIDERA and other small molecule products and product candidates, raw materials and supplies for production of products we manufacture, our fill-finish operations, the majority of our final product storage, and a substantial portion of our packaging operations. In addition, due to the unique manner in which our products are manufactured, we rely on single source providers of several raw materials and manufacturing supplies. These third parties are independent entities subject to their own unique operational and financial risks that are outside of our control. These third parties may not perform their obligations in a timely and cost-effective manner or in compliance with applicable regulations, and they may be unable or unwilling to increase production capacity commensurate with demand for our existing or future products. Finding alternative providers could take a significant amount of time and involve significant expense due to the specialized nature of the services and the need to obtain regulatory approval of any significant changes to our suppliers or manufacturing methods. We cannot be certain that we could reach agreement with alternative providers or that the FDA or other regulatory authorities would approve our use of such alternatives.

•

We rely on our manufacturing facilities in Research Triangle Park, North Carolina (RTP) and Hillerød, Denmark for the production of TYSABRI and our manufacturing facilities in RTP and Cambridge, Massachusetts for the production of AVONEX. Our global bulk supply of TYSABRI and AVONEX depends on the uninterrupted and efficient operation of these facilities, which could be adversely affected by equipment failures, labor shortages, natural disasters, power failures and numerous other factors. If we are unable to meet demand for TYSABRI or AVONEX for any reason, we would need to rely on a limited number of qualified third party contract manufacturers.

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We and our third party providers are generally required to maintain compliance with current Good Manufacturing Practices and other stringent requirements and are subject to inspections by the FDA and comparable agencies in other jurisdictions to confirm such compliance. Any delay, interruption or other issues that arise in the manufacture, fill-finish, packaging, or storage of our products as a result of a failure of our facilities or the facilities or operations of third parties to pass any regulatory agency inspection could significantly impair our ability to develop and commercialize our products. Significant noncompliance could also result in the imposition of monetary penalties or other civil or criminal sanctions and damage our reputation.

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new laws, regulations or judicial decisions, or new interpretations of existing laws, regulations or decisions, related to health care availability, pricing or marketing practices, compliance with wage and hour laws and other employment practices, method of delivery, payment for health care products and services, compliance with health information and data privacy and security laws and regulations, tracking and reporting payments and other transfers of value made to physicians and teaching hospitals, and extensive anti-bribery and anti-corruption prohibitions;

•	changes in the FDA and foreign regulatory approval processes that may delay or prevent the approval of new products and result in lost market opportunity; and

•	changes in FDA and foreign regulations that may require additional safety monitoring, labeling changes, restrictions on product distribution or use, or other measures after the introduction of our products to market, which could increase our costs of doing business, adversely affect the future permitted uses of approved products, or otherwise adversely affect the market for our products.

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•	the inability to obtain necessary foreign regulatory or pricing approvals of products in a timely manner;

•	collectability of accounts receivable;

•	fluctuations in currency exchange rates;

•	difficulties in staffing and managing international operations;

•	the imposition of governmental controls;

•	less favorable intellectual property or other applicable laws;

•	increasingly complex standards for complying with foreign laws and regulations that may differ substantially from country to country and may conflict with corresponding U.S. laws and regulations;

•	the emergence of far-reaching anti-bribery and anti-corruption legislation in the U.K., including passage of the U.K. Bribery Act 2010, and elsewhere and escalation of investigations and prosecutions pursuant to such laws;

•	compliance with complex import and export control laws;

•	restrictions on direct investments by foreign entities and trade restrictions;

•	greater political or economic instability; and

•	changes in tax laws and tariffs.

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•	the cost of restructurings;

•	impairments with respect to investments, fixed assets and long-lived assets, including in-process research and development and other intangible assets;

•	inventory write-downs for failed quality specifications, charges for excess or obsolete inventory and charges for inventory write downs relating to product suspensions, expirations or recalls;

•	bad debt expenses and increased bad debt reserves;

•	outcomes of litigation and other legal proceedings, regulatory matters and tax matters;

•	milestone payments under license and collaboration agreements; and

•	payments in connection with acquisitions and other business development activity.

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Item  1B.	Unresolved Staff Comments

Item  2.	Properties

•	729,000 square feet in Cambridge, Massachusetts, which is comprised of a 67,000 square foot biologics manufacturing facility and 662,000 square feet for our corporate headquarters, laboratory and additional office space;

•	357,000 square feet of office space in Weston, Massachusetts, of which 175,000 square feet has been subleased for a term which started in January 2014 and will continue through the remaining term of our lease agreement; and

•	46,000 square feet of warehouse space in Somerville, Massachusetts.

•	357,000 square feet of laboratory and office space;

•	175,000 square feet related to a large-scale biologics manufacturing facility;

•	105,000 square feet related to a biologics manufacturing facility;

•	60,000 square feet of warehouse space; and

•	43,000 square feet related to a large-scale purification facility.

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•	140,000 square feet of warehouse, utilities and support space;

•	70,000 square feet related to a label and packaging facility;

•	50,000 square feet of administrative space; and

•	50,000 square feet related to a laboratory facility.

Item  3.	Legal Proceedings

Item  4.	Mine Safety Disclosures

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Item 5.	Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

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Item 6.	Selected Financial Data

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(1)	Total cost and expenses includes the $110.0 million upfront payment made to Acorda Therapeutics, Inc. pursuant to our June 30, 2009 collaboration and license agreement to develop and commercialize products containing fampridine in markets outside the U.S.

(2)	Changes in tax law in certain state jurisdictions in which we operate and the resolution of multiple federal, state and foreign tax audits, including the effective settlement of several uncertain tax positions resulted in a $58.3 million reduction to our income tax expense.

(3)	Included in total cost and expenses is a charge to acquired in-process research and development of $40.0 million related to the achievement of a milestone by Biogen Idec Hemophilia, Inc. (formerly Syntonix Pharmaceuticals, Inc.).

(4)

Included in total cost and expenses is a charge to acquired in-process research and development of $205.0 million incurred in connection with the license agreement entered into with Knopp Neurosciences Inc. (Knopp), which we consolidated as we determined that we were the primary beneficiary of the entity. The $205.0 million charge was partially offset by an attribution of $145.0 million to the noncontrolling interest.

(5)	Our share of revenues from unconsolidated joint business reflects charges of $50.0 million in 2011 and $49.7 million in 2013 for damages and interest awarded to Hoechst in Genentech's arbitration with Hoechst for RITUXAN.

(6)	Biogen Idec Inc.’s shareholders’ equity reflects a reduction in additional paid in capital and noncontrolling interests totaling $187.3 million resulting from our purchase of the noncontrolling interest in our joint venture investments in Biogen Dompé SRL and Biogen Dompé Switzerland GmbH.

(7)	Gain on sale of rights relates to the sale of all of our rights, including rights to royalties, related to BENLYSTA.

(8)	Equity in loss of investee, net of tax relates to our ownership interest in Samsung Bioepis to develop, manufacture and market biosimilar pharmaceuticals.

(9)

Commencing in the second quarter of 2013, product revenues and total revenues includes 100% of net revenues related to sales of TYSABRI as a result of our acquisition of TYSABRI rights from Elan and net revenues related to sales of TECFIDERA, our new oral first-line treatment for people with relapsing forms of multiple sclerosis (MS), which was approved by the FDA and commenced commercial sales. In addition, upon the closing of our acquisition of TYSABRI rights, our collaboration agreement was terminated, and we no longer record collaboration profit sharing.

(10)	Included in net income is a $38.5 million benefit, net of ancillary federal and state income and non-income tax effects, related to years 2005 through 2012 as a result of receiving updated technical guidance from the IRS concerning our current and prior year filings and calculation of our U.S. federal manufacturing deduction and overall tax classification of our unconsolidated joint business.

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Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations

(1)	Commencing in the second quarter of 2013, product revenues and total revenues includes 100% of net revenues related to sales of TYSABRI as a result of our acquisition of TYSABRI rights from Elan and net revenues related to sales of TECFIDERA, our new oral first-line treatment for people with relapsing forms of MS, which was approved by the FDA and commenced commercial sales.

(2)	Our share of revenues from unconsolidated joint business reflects a charge of $49.7 million for damages and interest awarded to Hoechst in Genentech's arbitration with Hoechst for RITUXAN.

•	Worldwide AVONEX revenues totaled $3,005.5 million for 2013, representing an increase of 3.2% over 2012.

•	Worldwide TYSABRI revenues totaled $1,526.5 million for 2013, representing an increase of 34.4% over 2012. The increase in revenue is primarily due to 100% of net U.S. revenue being recognized starting in April 2013 as a result of our acquisition of TYSABRI rights.

•	Worldwide TECFIDERA revenues totaled $876.1 million for 2013. Approximately $134.0 million of U.S. TECFIDERA revenues in 2013 represent inventory in the channel.

•	Our share of revenues from unconsolidated joint business totaled $1,126.0 million for 2013, representing a decrease of 1.0% from 2012.

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Total cost and expenses increased 19.8% for 2013 compared to 2012. This increase resulted from a 69.6% increase in the amortization of acquired intangible assets, a 57.2% increase in cost of sales, a 34.0% increase in selling, general and administrative expense and an 8.2% increase in research and development expense, partially offset by a 73.1% decrease in collaboration profit sharing compared with the same period in 2012.

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•	We out-licensed or terminated certain research and development programs, including those in oncology and cardiovascular medicine, that were no longer a strategic fit for us.

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•	We completed a 13% reduction in workforce spanning our sales, research and development, and administrative functions.

•	We vacated and recognized the sale of the San Diego, California facility as well as consolidated certain of our Massachusetts facilities.

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•	$3.25 billion used for our acquisition of TYSABRI rights from Elan;

•	$643.2 million in total payments for income taxes;

•	$450.0 million used for the repayment of principal of our 6.0% Senior Notes;

•	$400.3 million used for share repurchases;

•	$246.3 million used for purchases of property, plant and equipment; and

•	$100.0 million upfront payment made to Isis pursuant to our collaboration agreement dated September 2013.

•	$133.2 million in cash collections on accounts receivable balances in Spain and Portugal as part of new programs to resolve outstanding amounts long overdue;

•	$67.5 million in proceeds from the issuance of stock for share-based compensation arrangements;

•	$46.8 million in proceeds from the sale of our royalty and other rights to BENLYSTA;

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•	$984.7 million used for share repurchases;

•	$526.6 million in total payments for income taxes;

•	$254.5 million used for purchases of property, plant and equipment;

•	$72.4 million of net cash paid for the acquisition of Stromedix, Inc.;

•	$71.0 million in upfront payments made to Isis, recognized as research and development expense, pursuant to our collaboration agreements dated January, June, and December 2012; and

•	$32.1 million in contributions made to Samsung Bioepis.

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•	Non-cash operating items such as depreciation and amortization, impairment charges and share-based compensation charges;

•	Changes in operating assets and liabilities which reflect timing differences between the receipt and payment of cash associated with transactions and when they are recognized in results of operations; and

•	Changes associated with the fair value of contingent milestones associated with our acquisitions of businesses and payments related to collaborations.

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(1)	We lease properties and equipment for use in our operations. In addition to rent, the leases may require us to pay additional amounts for taxes, insurance, maintenance and other operating expenses. Amounts reflected within the table, detail future minimum rental commitments under non-cancelable operating leases as of December 31 for each of the periods presented.

(2)

Includes future minimum rental commitments related to leases executed for two office buildings in Cambridge, Massachusetts, which completed construction in July and November 2013, net of sublease income expected to be received for the vacated portion of our Weston, MA facility. For additional information related to our leases, please read Note 11, Property, Plant and Equipment to our consolidated financial statements included in this report.

(3)	Notes payable includes principal and interest payments.

(4)	Purchase and other obligations include our obligations of approximately $23.5 million related to the fair value of net liabilities on derivative contracts, approximately $5.0 million related to fixed obligations for the purchase of natural gas and approximately $24.7 million related to obligations for communication services.

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•	estimating the timing of and expected costs to complete the in-process projects;

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•	projecting regulatory approvals;

•	estimating future cash flows from product sales resulting from completed products and in process projects; and

•	developing appropriate discount rates and probability rates by project.

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Item 7A.	Quantitative and Qualitative Disclosures About Market Risk

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Item 8.	Financial Statements and Supplementary Data

Item 9.	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

Item 9A.	Controls and Procedures

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•	pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect our transactions and dispositions of our assets;

•	provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with U.S. GAAP, and that our receipts and expenditures are being made only in accordance with authorizations of our management and directors; and

•	provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of our assets that could have a material effect on our financial statements.

Item 9B.	Other Information

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Item 10.	Directors, Executive Officers and Corporate Governance

Item 11.	Executive Compensation

Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13.	Certain Relationships and Related Transactions, and Director Independence

Item 14.	Principal Accountant Fees and Services

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Item 15.	Exhibits and Financial Statement Schedules

a.	(1) Consolidated Financial Statements:

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1.	Summary of Significant Accounting Policies

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Medicaid rebates relate to our estimated obligations to states under established reimbursement arrangements. Rebate accruals are recorded in the same period the related revenue is recognized resulting in a reduction of product revenue and the establishment of a liability which is included in other current liabilities. Our liability for Medicaid rebates consists of estimates for claims that a state will make for the current quarter, claims for prior quarters that have been estimated for which an invoice has not been received, invoices received for claims from the prior quarters that have not been paid, and an estimate of potential claims that will be made for inventory that exists in the distribution channel at period end.

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Governmental rebates or chargebacks, including VA and PHS discounts, represent our estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices we charge to wholesalers which provide those products. The wholesaler charges us for the difference between what the wholesaler pays for the products and the ultimate selling price to the qualified healthcare providers. Rebate and chargeback reserves are established in the same period as the related revenue is recognized resulting in a reduction in product revenue and accounts receivable. Chargeback amounts are generally determined at the time of resale to the qualified healthcare provider from the wholesaler, and we generally issue credits for such amounts within a few weeks of the wholesaler notifying us about the resale. Our reserves for VA, PHS and chargebacks consists of amounts that we expect to issue for inventory that exists at the wholesalers that we expect will be sold to qualified healthcare providers and chargebacks that wholesalers have claimed for which we have not issued a credit.

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Managed care rebates represent our estimated obligations to third parties, primarily pharmacy benefit managers. Rebate accruals are recorded in the same period the related revenue is recognized resulting in a reduction of product revenue and the establishment of a liability which is included in accrued expenses and other current liabilities. These rebates result from performance-based goals that are primarily based on attaining contractually specified sales volumes and growth and price increase limit allowances (price protection). The calculation of the accrual for these rebates is based on an estimate of the customer’s buying patterns and the resulting applicable contractual rebate rate(s) to be earned over a contractual period.

•	Other governmental rebates or applicable allowances primarily relate to mandatory rebates and discounts in markets where government-sponsored healthcare systems are the primary payors for healthcare.

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•	Level 1 — Fair values are determined utilizing quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access;

•	Level 2 — Fair values are determined by utilizing quoted prices for identical or similar assets and liabilities in active markets or other market observable inputs such as interest rates, yield curves and foreign currency spot rates; and

•	Level 3 — Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable.

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2.	Acquisitions

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3.	Gain on Sale of Rights

4.	Accounts Receivable

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6.	Inventory

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7.	Intangible Assets and Goodwill

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8.	Fair Value Measurements

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10.	Derivative Instruments

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11.	Property, Plant and Equipment

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12.	Indebtedness

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13.	Equity

14.	Accumulated Other Comprehensive Income (Loss)

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15.	Earnings per Share

16.	Share-based Payments

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(a)

MSUs granted in 2013 include approximately 18,000 and 39,000 MSUs issued in 2013 based upon the attainment of performance criteria set for 2012 and 2011, respectively, in relation to shares granted in those years. The remainder of MSUs granted during 2013 include awards granted in conjunction with our annual awards made in February 2013 and MSUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.

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(a)

CSPSs granted in 2013 include approximately 76,000 CSPSs issued in 2013 based upon the attainment of performance criteria set for 2012 in relation to shares granted in 2012. The remainder of the CSPSs granted in 2013 include awards granted in conjunction with our annual awards made in February 2013 and CSPSs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.

(a)	RSUs granted in 2013 primarily represent RSUs granted in conjunction with our annual awards made in February 2013 and awards made in conjunction with the hiring of new employees. RSUs granted in 2013 also include approximately 16,000 RSUs granted to our Board of Directors.

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17.	Income Taxes

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18.	Other Consolidated Financial Statement Detail

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19.	Investments in Variable Interest Entities

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20.	Collaborative and Other Relationships

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(1)	Net revenue represents Biogen Idec’s pre-tax receipts from third-party distributors, less expenses incurred by Biogen Idec in the conduct of commercialization activities supporting the distributor activities.

(2)	The Biogen Idec Distributor Territory represents Biogen Idec territories where sales are derived utilizing a third-party distributor.

(3)	A credit will be issued to Sobi against its reimbursement of the Opt-in Consideration in an amount equal to the difference in the rate paid by Biogen Idec to Sobi on sales in the Biogen Idec territories for certain periods prior to the first commercial sale in the Sobi Territory versus the rate that otherwise would have been payable on such sales.

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21.	Litigation

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22.	Commitments and Contingencies

(1)

Includes future minimum rental commitments related to leases executed for two office buildings in Cambridge, Massachusetts, which completed construction in July and November 2013. The leases both have 15 year terms and we have options to extend the term of each lease for two additional five-year terms. Future minimum rental commitments under these leases will total approximately $340.0 million over the initial 15 year lease terms.

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23.	Guarantees

24.	Employee Benefit Plans

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25.	Segment Information

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(1)	Represents amounts related to Europe less those attributable to Germany.

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26.	Quarterly Financial Data (Unaudited)

(a)	Our share of revenues from unconsolidated joint business reflects a charge of $41.5 million for damages and interest awarded to Hoechst in Genentech's arbitration with Hoechst for RITUXAN.

(b)

Product revenues and total revenues for the second, third and fourth quarters of 2013 includes 100% of net revenues related to sales of TYSABRI as a result of our acquisition of TYSABRI rights from Elan on April 2, 2013 and net revenues related to sales of TECFIDERA, our new oral first-line treatment for people with relapsing forms of multiple sclerosis (MS), which was approved by the FDA in March 2013 and commenced commercial sales in April 2013.

(c)	Net income and net income attributable to Biogen Idec Inc., for the third quarter of 2013, includes a charge to research and development expense of $75.0 million related to an upfront payment made in connection with our collaboration agreement entered into with Isis.

(d)	Net income and net income attributable to Biogen Idec Inc. for the first quarter of 2012 includes a charge to research and development expense of $29.0 million related to an upfront payment made in connection with our development agreement entered into with Isis.

(e)	Net income and net income attributable to Biogen Idec Inc. for the fourth quarter of 2012 includes the correction of an error that had accumulated over several prior years in our deferred tax accounting for capitalized interest which resulted in an expense of $29.0 million.

(f)	Net income and net income attributable to Biogen Idec Inc. for the fourth quarter of 2012 includes a charge to research and development expense of $30.0 million related to an upfront payment made in connection with our development agreement entered into with Isis.

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