SCHEDULE 13D/A 0001755163 XXXXXXXX LIVE 18 Common Stock 08/06/2025 false 0001283699 872590104 T-Mobile US, Inc.

12920 SE 38TH STREET BELLEVUE WA 98006

Kenneth A. Siegel, Esq. 81-3-3214-6522 Shin-Marunouchi Building, 29th Floor 5-1, Marunouchi 1-Chome Chiyoda-ku, Tokyo M0 100-6529 John Horsfield-Bradbury, Esq. 44 20 7959 8491 1 New Fetter Lane London X0 EC4A 1AN Robert G. DeLaMater, Esq. 1-212-558-4788 125 Broad Street New York NY 10004 0001755163 N SoftBank Group Capital Limited N X0 0 0 0 0 0 N 0.00 CO Y Delaware Project 4 L.L.C. N DE 0.0 0.00 0.00 0.00 0.00 N 0.00 OO Y Delaware Project 6 L.L.C. N DE 0 0 32861065.00 0 32861065.00 N 2.92 OO (1) Based on the number of shares of Common Stock outstanding on July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. (The terms used above are defined in the Explanatory Note of this Schedule 13D). Y Delaware Project 9 L.L.C. N DE 0.00 0.00 18000000.00 0.00 18000000.00 N 1.60 OO (1) Based on the number of shares of Common Stock outstanding on July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. (The terms used above are defined in the Explanatory Note of this Schedule 13D). Y SoftBank Group Corp. N M0 0.00 0 50861065.00 0.00 50861065.00 N 4.52 HC CO (1) As of the date hereof, the shares of Common Stock are held by Project 6 LLC, a wholly owned subsidiary of SoftBank, and Project 9 LLC, a wholly owned subsidiary of SoftBank; the shares of Common Stock held by Project 6 LLC and Project 9 LLC are subject to the Proxy Agreement. (2) Based on the number of shares of Common Stock outstanding on July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. (The terms used above are defined in the Explanatory Note of this Schedule 13D). Common Stock T-Mobile US, Inc. 12920 SE 38TH STREET BELLEVUE WA 98006 EXPLANATORY NOTE This Amendment No. 18 (this "Schedule 13D Amendment") to the Schedule 13D filed with the U.S. Securities and Exchange Commission (the "Commission") on April 2, 2020, as amended and supplemented by Amendment No. 1 to the Schedule 13D filed with the Commission on June 15, 2020, Amendment No. 2 to the Schedule 13D filed with the Commission on June 25, 2020, Amendment No. 3 to the Schedule 13D filed with the Commission on June 26, 2020, Amendment No. 4 to the Schedule 13D filed with the Commission on July 30, 2020, Amendment No. 5 to the Schedule 13D filed with the Commission on October 6, 2020, Amendment No. 6 to the Schedule 13D filed with the Commission on September 7, 2021, Amendment No. 7 to the Schedule 13D filed with the Commission on September 9, 2021, Amendment No. 8 to the Schedule 13D filed with the Commission on September 16, 2021, Amendment No. 9 to the Schedule 13D filed with the Commission on September 28, 2021, Amendment No. 10 to the Schedule 13D filed with the Commission on February 4, 2022, Amendment No. 11 to the Schedule 13D filed with the Commission on March 29, 2022, Amendment No. 12 to the Schedule 13D filed with the Commission on April 13, 2022, Amendment No. 13 to the Schedule 13D filed with the Commission on June 6, 2023, Amendment No. 14 to the Schedule 13D filed with the Commission on December 26, 2023, Amendment No. 15 to the Schedule 13D filed with the Commission on June 11, 2024, Amendment No. 16 to the Schedule 13D filed with the Commission on July 2, 2024 and Amendment No. 17 to the Schedule 13D filed with the Commission on June 20, 2025 (as amended and supplemented, this "Schedule 13D"), is being filed on behalf of SoftBank Group Corp., a Japanese kabushiki kaisha ("SoftBank"), its wholly owned subsidiary SoftBank Group Capital Limited, a private limited company incorporated in England and Wales ("SBGC"), SoftBank's wholly owned subsidiary Delaware Project 6 L.L.C., a Delaware limited liability company ("Project 6 LLC"), SoftBank's wholly owned subsidiary, Delaware Project 4 L.L.C., a Delaware limited liability company ("Project 4 LLC"), and SoftBank's wholly owned subsidiary, Delaware Project 9, L.L.C., a Delaware limited liability company ("Project 9 LLC," and together with SoftBank, SBGC, Project 6 LLC and Project 4 LLC, the "Reporting Persons"), with respect to the common stock of T-Mobile US, Inc., a Delaware corporation ("T-Mobile" or the "Issuer"), par value $0.00001 per share (the "Common Stock"). Other than as set forth below, all Items in the Schedule 13D are materially unchanged. Capitalized terms used in this Schedule 13D Amendment which are not defined herein have the meanings given to them in this Schedule 13D. Item 4 of the Schedule 13D is hereby amended to include the following: On August 6, 2025, Project 4 LLC, Project 6 LLC and Project 9 LLC collectively sold an aggregate of 13,000,000 shares of Common Stock in an unregistered block sale transaction with an unaffiliated broker dealer pursuant to Rule 144 under the Securities Act of 1933, as amended (the "Block Sale") for net proceeds of approximately $3.02 billion, representing approximately 1.16% of the shares of Common Stock outstanding as of July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. Project 4 LLC sold 3,566,400 shares of Common Stock, Project 6 LLC sold 182,043 shares of Common Stock and Project 9 LLC sold 9,251,557 shares of Common Stock. The Block Sale was undertaken as part of the Reporting Persons' normal course evaluation of their investment. Although the Reporting Persons do not have any specific plan or proposal to effect further sales of shares of Common Stock at the time of this filing, the Reporting Persons intend to monitor and evaluate their investment on an ongoing basis. As a result of the Block Sale, the Reporting Persons no longer collectively beneficially own greater than five percent of the number of shares of Common Stock outstanding and therefore this Amendment No. 18 represents the final amendment to the Schedule 13D and the Reporting Persons shall cease to be Reporting Purposes immediately after the filing of this Amendment No. 18. Item 5 of the Schedule 13D is hereby amended to include the following: The information contained in the cover pages of this Schedule 13D is incorporated herein by reference. The information contained in the cover pages of this Schedule 13D is incorporated herein by reference. The information contained in Item 4 of this Schedule 13D is herein incorporated by reference. Other than as set forth in this Schedule 13D Amendment, none of the Reporting Persons nor, to the best of each Reporting Person's knowledge, any person on Appendix A-1, Appendix A-2, Appendix A-3, Appendix A-4 or Appendix A-5 (each as previously filed with the Schedule 13D), has engaged in any transaction in any shares of Common Stock since the filing of Amendment No. 17 to the Schedule 13D on June 20, 2025. The Reporting Persons collectively ceased to have beneficial ownership of greater than five percent of the number of shares of Common Stock outstanding on August 6, 2025. SoftBank Group Capital Limited /s/ Stephen Lam 08/08/2025 Delaware Project 4 L.L.C. /s/ Hugh Manahan 08/08/2025 Delaware Project 6 L.L.C. /s/ Hugh Manahan 08/08/2025 Delaware Project 9 L.L.C. /s/ Hugh Manahan 08/08/2025 SoftBank Group Corp. /s/ Yuko Yamamoto 08/08/2025