T-Mobile US, Inc. filed a Form 8-K on October 28, 2026, reporting that G. Michael Sievert notified the Board of Directors on October 26, 2026 of his decision to resign from the Board and its Transaction Committee, effective November 1, 2026.

Key Highlights

  • Resignation notified: G. Michael Sievert informed the Board of Directors on October 26, 2026 of his intent to resign.
  • Effective date: The resignation from the Board, its Transaction Committee, and the role of Vice Chair takes effect November 1, 2026.
  • Employment agreement link: The effective date coincides 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.
  • No disagreement stated: According to the filing, Mr. Sievert's resignation "is not the result of any disagreement with the Company on any matter relating to its operations, policies or practices."
  • Roles ceasing: Mr. Sievert will cease to serve as Vice Chair of the Board and the Company as of November 1, 2026.

Sievert Departure Details and Context from the Filing

According to the Form 8-K filed by T-Mobile US, Inc. (NASDAQ:TMUS) on October 28, 2026, G. Michael Sievert notified the Board of Directors on October 26, 2026 of his decision to resign from the Board and its Transaction Committee. The filing reports that the effective date of November 1, 2026 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.

The filing further discloses that effective November 1, 2026, Mr. Sievert will also cease to serve as Vice Chair of the Board and the Company. The 8-K was filed under Item 5.02, which covers departures of directors or certain officers, elections of directors, appointments of certain officers, and compensatory arrangements of certain officers. The report was signed by Peter Osvaldik, Chief Financial Officer, on behalf of T-Mobile US, Inc.

The Company stated in the filing that Mr. Sievert's resignation "is not the result of any disagreement with the Company on any matter relating to its operations, policies or practices." No further details regarding successor arrangements or related compensatory changes were disclosed in this filing.

What Was Disclosed

T-Mobile US, Inc. disclosed in this 8-K that G. Michael Sievert will resign from the Board, its Transaction Committee, and his role as Vice Chair, all effective November 1, 2026, with the Company stating no disagreement prompted the departure.