AT&T Inc., an abbreviation for its predecessor's former name, the
American Telephone and Telegraph Company, is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's third largest telecommunications company by revenue and the third largest wireless carrier in the United States behind T-Mobile and Verizon. As of 2023, AT&T was ranked 32nd on the
Fortune 500 rankings of the largest United States corporations, with revenues of $122.4 billion.