A Regional Bell Operating Company (RBOC) was a corporate entity created as result of the antitrust lawsuit by the U.S. Department of Justice against the American Telephone and Telegraph Company (AT&T) in 1974 (United States v. AT&T) and settled in the Modification of Final Judgment on January 8, 1982.
AT&T agreed to divest its local exchange service operating companies, effective January 1, 1984. The group of local operating companies were split into seven independent Regional Bell Operating Companies, which became known as the Baby Bells.[1]
RBOCs were originally known as Regional Holding Companies (RHCs). Three companies still exist that have an RBOC as a predecessor: AT&T, Verizon, and Lumen Technologies (formerly CenturyTel and CenturyLink). Some other companies are holding onto smaller segments of the companies.