(Regional Bell Operating Company) The Bell telephone companies that were spun off from AT&T by court order in 1984 (the Divestiture). Also known as the "Baby Bells," the initial seven RBOCs were Nynex, Bell Atlantic, BellSouth, Southwestern Bell, US West, Pacific Telesis and Ameritech. By 2007, mergers reduced the number to three: AT&T, Verizon and Qwest (see below). See Divestiture and Telecommunications Act of 1996.

   Company   Baby Bells

   AT&T      Ameritech, Southwestern Bell
             BellSouth, Pacific Telesis

   Verizon   Nynex, Bell Atlantic

   Qwest     US West