The Numbers and Small Print Honest and straightforward communications, backed by credible data, is what we’re about. This report covers the domestic operations and activities of T-Mobile US, Inc. for the calendar year 2021 (January 1 to December 31), unless otherwise stated. It has been prepared in accordance with the Global Reporting Initiative (GRI) Standards: Core option. It is also aligned to the disclosure requirements of the Sustainability Accounting Standards Board (SASB) Standards for our industry. Information Integrity T-Mobile management is responsible for the preparation and integrity of the information reported for calendar year 2021. Through a system of internal controls, including a comprehensive verification process involving internal subject matter experts, we believe this information accurately represents our domestic responsibility activities and performance results for the calendar year. We continued to improve our data collection process by utilizing a centralized ESG collection tool which allows the internal subject matter experts to collaborate, collect data, and streamline our extensive review and approval process. External verification over specified GHG and energy metrics is provided by Apex Companies, LLC. THE ENVIRONMENT OUR GOVERNANCE OUR COMMUNITIES OUR PEOPLE 2021 CORPORATE RESPONSIBILITY REPORT 64 OUR COMPANY THE NUMBERS AND SMALL PRINT