AT&T Inc. is an American multinational telecommunications conglomerate, headquartered at Whitacre Tower in downtown Dallas, Texas. AT&T is the world's largest telecommunications company. AT&T is the second largest provider of mobile telephone services and the largest provider of fixed telephone services in the United States, and also provides broadband subscription television services through DirecTV; combined with AT&T's legacy U-verse service, this also makes AT&T the largest pay-television operator. AT&T is the second-largest company in Texas, behind ExxonMobil. As of February 2017, AT&T is the 12th largest company in the world (non-oil and overall) as measured by a composite of revenues, profits, assets and market valuation. AT&T is the largest telecommunications company in the world by revenue. As of 2017, it is also the 18th-largest mobile telecom operator in the world, with 134 million mobile customers. AT&T was ranked at #4 on the 2017 rankings of the world's most valuable brands published by Brand Finance.
AT&T Inc. began its history as Southwestern Bell Telephone Company (subsidiary of Bell Telephone Company, later AT&T Corporation) created in 1882. The divestiture of the American Telephone and Telegraph Company (founded 1885, later AT&T Corporation) followed the 1982 United States v. AT&T antitrust lawsuit. Southwestern Bell Corporation changed its name to SBC Communications Inc. in 1995. In 2005, SBC purchased former parent AT&T Corporation 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.
The current AT&T reconstitutes much of the former Bell System and includes ten of the original 22 Bell Operating Companies, along with the original long distance division.