X5 Mobile

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 T-Mobile brand is present in 12 European countries – Austria, Croatia, Czech Republic, Germany , 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. T-Mobile International is 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.