T-Mobile International AG is a holding company for Deutsche Telekom AG's various mobile communications subsidiaries outside Germany. Based in Bonn, Germany, its subsidiaries operate GSM, UMTS and LTE-based cellular networks in Europe, the United States, Puerto Rico, and the U.S. Virgin Islands. The company has financial stakes in mobile operators in both Central and Eastern Europe.
T-Mobile US, Inc. is the American operating entity of T-Mobile International AG. Its headquarters are located in Bellevue, Washington. T-Mobile US provides wireless voice, messaging, and data services in the United States, Puerto Rico and the U.S. Virgin Islands under the T-Mobile, MetroPCS and GoSmart Mobile brands.