United states securities and exchange commission

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 21
New Accounting Pronouncements
From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board 
(FASB) or other standard setting bodies that we adopt as of the specified effective date. Unless otherwise discussed 
below, we do not believe that the adoption of recently issued standards have or may have a material impact on our 
consolidated financial statements or disclosures.
In May 2014 the FASB issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with 
Customers (Topic 606), which supersedes all existing revenue recognition requirements, including most industry-
specific guidance. This new standard requires a company to recognize revenue when it transfers goods or services to 
customers in an amount that reflects the consideration that the company expects to receive for those goods or 
services. The FASB subsequently issued amendments to ASU No. 2014-09 that have the same effective date and 
transition date. These new standards became effective for us on January 1, 2018, and will be adopted using the 
modified retrospective method through a cumulative-effect adjustment directly to retained earnings as of that date. 
We have performed a review of these new standards as compared to our current accounting policies for customer 
contracts and collaborative relationships. During the fourth quarter of 2017 we finalized our assessments over the 
impact that these new standards will have on our consolidated results of operations, financial position and 
disclosures. As of December 31, 2017, we have not identified any accounting changes that would materially impact 
the amount of reported revenues with respect to our product revenues, revenues from anti-CD20 therapeutic 
programs or other revenues; however, the adoption of these new standards may result in a change in the timing of 
revenue recognition related to certain of our contract manufacturing activities. As of December 31, 2017, we expect 
to recognize an immaterial adjustment to retained earnings reflecting the cumulative impact for the accounting 
changes related to certain contract manufacturing arrangements made upon adoption of these new standards.
In January 2016 the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): 
Recognition and Measurement of Financial Assets and Financial Liabilities. This new standard amends certain aspects 
of accounting and disclosure requirements for financial instruments, including the requirement that equity 
investments with readily determinable fair values are to be measured at fair value with any changes in fair value 
recognized in a company's results of operations. This new standard does not apply to investments accounted for 
under the equity method of accounting or those investments that result in consolidation of the investee. Equity 
investments that do not have readily determinable fair values may be measured at fair value or at cost minus 
impairment adjusted for changes in observable prices. A financial liability that is measured at fair value in 
accordance with the fair value option is required to be presented separately in other comprehensive income for the 
portion of the total change in the fair value resulting from change in the instrument-specific credit risk. In addition, a 
valuation allowance should be evaluated on deferred tax assets related to available-for-sale debt securities in 
combination with other deferred tax assets. This new standard became effective for us on January 1, 2018. Based 
on our current investment holdings, the adoption of this new standard is not expected to have a material impact on 
our consolidated financial position or results of operations; however, it will result in the reclassification of where we 
recognize changes in fair value related to certain investments prospectively.
In February 2016 the FASB issued ASU No. 2016-02, Leases (Topic 842). This new standard establishes a right-
of-use (ROU) model that requires all lessees recognize right-of-use assets and liabilities on their balance sheet that 
arise from leases with terms longer than 12 months as well as provide disclosures with respect to certain qualitative 
and quantitative information related to their leasing arrangements. This new standard will become effective for us on 
January 1, 2019. A modified retrospective transition approach is required for leases existing at, or entered into after, 
the beginning of the earliest comparative period presented in the financial statements, with certain practical 
expedients available. While we are currently evaluating the impact that this new standard may have on our 
consolidated results of operations, financial position and disclosures, we expect that the adoption of this new 
standard may materially affect the reported amount of total assets and total liabilities within our consolidated 
balance sheet with no material impact to our consolidated statement of income. We are unable to quantify the 
impact at this time as the ultimate impact of adopting this new standard will depend on the total amount of our 
lease commitments as of the adoption date. 
In March 2016 the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718): 
Improvements to Employee Share-Based Payment Accounting. This new standard requires recognition of the income 
tax effects of vested or settled awards in the income statement and involves several other aspects of the accounting 
for share-based payment transactions, including the income tax consequences and classification of awards as either 
equity or liabilities in the statement of cash flows. This new standard became effective for us on January 1, 2017. 
The adoption of this new standard did not have a material impact on our consolidated financial position, results of 

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