T-Mobile International AG was a German holding company for Deutsche Telekom AG’s various mobile communications subsidiaries outside Germany. Based in Bonn, Germany, its subsidiaries operated GSM, UMTS and LTE-based cellular networks in Europe, the United States, Puerto Rico, and the U.S. Virgin Islands. The company had financial stakes in mobile operators in both Central and Eastern Europe.
The T-Mobile brand was present in 12 European countries – Austria, Croatia, Czech Republic, Germany (as Telekom), Hungary, Republic of Macedonia, Montenegro, the Netherlands, Poland, Romania, Slovakia, and the United Kingdom, as well as the United States, Puerto Rico, and the U.S. Virgin Islands.
Globally, T-Mobile International subsidiaries had a combined total of approximately 230 million subscribers. T-Mobile International was the world’s fifteenth-largest mobile-phone service provider by subscribers and the fourth-largest multinational after the UK’s Vodafone, India’s Airtel, and Spain’s Telefónica.