AT&T vs T-Systems

AT&T Inc. is an American multinational telecommunications corporation, headquartered at Whitacre Tower in downtown Dallas, Texas. AT&T Inc. began its existence as Southwestern Bell Corporation, one of seven Regional Bell Operating Companies created in 1983 in the divestiture of the American Telephone and Telegraph Company following the 1982 United States v. AT&T antitrust lawsuit. Southwestern Bell changed its name to SBC Communications Inc. in 1995. In 2005, SBC purchased former parent AT&T Corp. and took on its branding, with the merged entity naming itself AT&T Inc. and using the iconic AT&T Corp. logo and stock-trading symbol.

T-Systems is a German global IT services and consulting company headquartered in Frankfurt. Founded in October 2000, it is a subsidiary of Deutsche Telekom. The company operates in more than 20 countries and employs approximately 50,000 people worldwide, among them around 27,000 in Germany and 27,000 outside. Since December 2007 Reinhard Clemens is the CEO. Before that, he was president of EDS Germany since 2003.