Item 9B. Other Information

On November 16, 2023, G. Michael Sievert, President and Chief Executive Officer, adopted a trading plan intended to satisfy the affirmative defense of Rule 10b5-1(c) to sell up to 160,000 shares of T-Mobile US, Inc. common stock between February 27, 2024, and November 12, 2024, subject to certain conditions. The duration of this trading plan is 362 days.

On November 21, 2023, Peter Osvaldik, Executive Vice President and Chief Financial Officer, adopted a trading plan intended to satisfy the affirmative defense of Rule 10b5-1(c) to sell up to 20,000 shares of T-Mobile US, Inc. common stock between February 20, 2024, and November 15, 2024, subject to certain conditions. The duration of this trading plan is 360 days.

On November 16, 2023, Callie Field, President, Business Group, adopted a trading plan intended to satisfy the affirmative defense of Rule 10b5-1(c) to sell all of her T-Mobile US, Inc. common stock to be acquired on March 4, 2024, upon the vesting of certain time-based restricted stock unit awards and performance-based restricted stock unit awards (“PRSUs”), up to a total of 26,407 shares assuming PRSUs will vest at maximum value, subject to certain conditions. The duration of this trading plan is 134 days.

On November 9, 2023, Michael Katz, President, Marketing, Strategy and Products, adopted a trading plan intended to satisfy the affirmative defense of Rule 10b5-1(c) to sell up to 23,748 shares of T-Mobile US, Inc. common stock between February 15, 2024, and December 31, 2024, subject to certain conditions. The duration of this trading plan is 418 days.