T-Mobile US is majority-owned by Deutsche Telekom (DT), the German telecommunications company. DT has held a controlling stake in T-Mobile US since the early 2000s, and as of recent years DT’s ownership has hovered around just over 50% of the company’s shares, making DT the largest and controlling shareholder. DT's stake was reinforced via share purchases and mergers-related adjustments in the 2020s, solidifying its majority position. For the latest precise percentage, check the most recent DT investor disclosures or T-Mobile US annual reports, as the stake can fluctuate with share transactions and secondary offerings.