AT&T is the largest telecommunications company, second largest provider of mobile telephone services, and the largest provider of fixed telephone services in the United States. AT&T began as Southwestern Bell Telephone Company, one of seven Regional Bell Operating Companies (RBOC) created in 1982 in the divestiture of the American Telephone and Telegraph Company. AT&T Mobility is a wholly owned subsidiary of AT&T that provides wireless services to 138.8 million subscribers in the United States, including Puerto Rico and the US Virgin Islands, and is the second largest wireless telecommunications provider in the US and Puerto Rico behind Verizon Wireless.