Who Is in Your Fave 5 ? T-Mobile is a mobile network operator headquartered in Bonn, Germany. It is a subsidiary of Deutsche Telekom and belongs to the FreeMove Business alliance. T-Mobile USA is the United States based subsidiary of T-Mobile International AG. The US company was previously known as VoiceStream Wireless or Powertel. In May 2001, VoiceStream was acquired by Deutsche Telekom for US$24 billion, and in September 2002 changed the company name nationally to T-Mobile. Headquartered in Factoria, Bellevue, Washington, T-Mobile USA is currently the fourth-largest wireless carrier in the U.S. market with approximately 27 million customers as of August 2007 and annual revenue of US$17.1 billion. The US T-Mobile network predominately uses the GSM/GPRS 1900 MHz frequency-band, making it the largest 1900 MHz network in the US. Service is available in 46 of the top 50 US markets, reaching 244 million potential customers. By mid-2008 the network is forecast to expand to 98 of 100 largest markets and 259 million potential customers.