T-Mobile Vice Chair Michael Sievert To Resign From Board And Transaction Committee, Effective November 1, 2026

On October 26, 2026, G. Michael Sievert notified the Board of Directors (the "Board") of T-Mobile US, Inc. (the "Company") of his decision to resign from the Board and its Transaction Committee, effective November 1, 2026. The effective date of Mr. Sievert’s resignation is concurrent with the expiration of the Amendment, dated September 19, 2025, to the Amended and Restated Employment Agreement, dated March 9, 2023, between the Company and Mr. Sievert. Effective November 1, 2026, Mr. Sievert will also cease to serve as Vice Chair of the Board and the Company.