TMUS: Leadership change

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. 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. Mr. Sievert’s resignation is not the result of any disagreement with the Company on any matter relating to its operations, policies or practices. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. T-MOBILE US, INC. October 28, 2026 /s/ Peter Osvaldik Name: Peter Osvaldik Title: Chief Financial Officer