OUR PURPOSE PIONEERING SCIENCE 115 BIOGEN 2021 YEAR IN REVIEW PATIENTS OUR PEOPLE ENVIRONMENT COMMUNITY REPORTING REPORTING Advancing transparency on material ESG issues EXECUTIVE SUMMARY 2021 SNAPSHOT As a science-based company, we believe in the power of data to help identify opportunities, shape strategy and track progress. Data disclosure can build trust, and Biogen has long been responsive to evolving stakeholder expectations around transparent reporting on material ESG issues. In 2021, we conducted a new materiality assessment, reaching out to over 5,000 stakeholders, spanning employees, healthcare professionals, patient advocates, government officials, and community groups. More than 94% of respondents see Biogen as a pioneer in neuroscience, with broad strengths in R&D pipeline and innovation; disease awareness and treatment; patient advocacy; environmental issues, notably climate change and water; DE&I and racial justice; community engagement and philanthropy; and economic performance. We also heard that stakeholders want us to do even more to address health access and equity and health systems strengthening, as well as talent recruitment and retention, priorities we share. Those perspectives have helped inform our ESG priorities and our approach to reporting. Biogen’s 2021 Year in Review was prepared in accordance with the Global Reporting Initiative (GRI) Standards, informed by the Task Force on Climate-related Financial Disclosures (TCFD) and the United Nations Sustainable Development Goals (SDGs). As we continue to seek new ways to address stakeholder interests through the highest standards of reporting, this year we have more fully aligned data disclosures with the core Stakeholder Capitalism Metrics, published by the International Business Council of the World Economic Forum in 2020. In 2022, Biogen was proud to join the United Nations Global Compact Communication on Progress as an early adopter, as part of our commitment to transparently disclosing our contribution to the United Nations Sustainable Development Goals. Þ WWW.GLOBALREPORTING.ORG Þ WWW.SASB.ORG/STANDARDS Þ SDGS.UN.ORG/GOALS Þ WWW.WEFORUM.ORG Þ WWW.FSB-TCFD.ORG Evolving stakeholder expectations for data disclosure We understand that a range of stakeholders want to know about corporate ESG performance. According to Marsh & McLennan , companies most attractive to students and young professionals have ESG scores 25% higher than the global average. Gartner found 85% of investors consider ESG factors in their investments, yet only one in 10 find the ESG information they want in corporate disclosures. Biogen continually strives to enhance the ways we track and report material ESG data, in line with stakeholder interests and global standards. In 2021, we released our first Diversity, Equity and Inclusion (DE&I) report, including EEO-1 data, global pay equity data, and workforce data breakdowns. Reflecting our efforts to be a catalyst for positive change on climate and health, we also disclosed air pollution data, notably NOx, SOx, and VOCs. As we continue to seek new ways to address stakeholder interests through the highest standards of reporting, this year we have more fully aligned data disclosures with the core Stakeholder Capitalism Metrics, published by the International Business Council of the World Economic Forum in 2020. We have continued reporting in accordance with the Global Reporting Initiative (GRI), as we have since 2013, as well as guidelines from the Sustainability Accounting Standards