GRI Index Continued Disclosure# Disclosure Topic 2021 Response 102-54 Claims of reporting in accordance with the GRI Standards This report has been prepared in accordance with the GRI Standards: Core option. 102-55 GRI content index 2021 Corporate Responsibility Report: The Numbers and Small Print > GRI Content Index 102-56 External assurance Third-party limited assurance was provided for T-Mobile’s greenhouse gas (GHG) emissions and energy use data for calendar year 2021. See T-Mobile’s Assurance Statement on our reporting page for more information. Economic Disclosures Material Topic: Digital Equity GRI 203: Indirect economic impacts 103-1 Explanation of the material topic and its boundaries 2021 Corporate Responsibility Report: Our Company > ESG Approach 2021 Corporate Responsibility Report: The Numbers and Small Print > Material Topic Definitions 103-2 The management approach and its components 2021 Corporate Responsibility Report: Our Communities > Digital Equity 103-3 Evaluation of the management approach 2021 Corporate Responsibility Report: Our Company > ESG Approach 2021 Corporate Responsibility Report: Our Communities > Digital Equity 203-1 Infrastructure investments and services supported 2021 Corporate Responsibility Report: Our Communities > Digital Equity Environmental Disclosures Material Topic: Energy Management GRI 302: Energy management 103-1 Explanation of the material topic and its boundaries 2021 Corporate Responsibility Report: Our Company > ESG Approach 2021 Corporate Responsibility Report: The Numbers and Small Print > Material Topic Definitions 103-2 The management approach and its components Environmental Policy CDP Climate Change Response 2021 Corporate Responsibility Report: The Environment > Energy Management 2021 CORPORATE RESPONSIBILITY REPORT OUR PEOPLE OUR GOVERNANCE OUR COMMUNITIES THE ENVIRONMENT THE NUMBERS AND SMALL PRINT 74 OUR COMPANY