T-Mobile International AG, known as T-Mobile, is an international wireless network operator based in Germen and subsidiaries in eastern Europe, American and Southeastern Asia. Having about 109 million users, T-Mobile International AG is considered one of the the largest mobile phone operators in the world. T-Mobile US, Inc. is the American operating entity belong to T-Mobile International AG. In the United States, T-Mobile provides wireless voice, messaging, and data service. As the fourth largest wireless network in American, T-Mobile has set over 4500 WiFi hotpots in airports, airport clubs, Starbucks, Kinkos，Borders Books and Music and other areas. T-Mobile is the third largest mobile operator in the US. As the rapidly increasing of its users, T-Mobile came into the market on the New York Stock Exchange in 2013.