Regional Bell Operating Company

A Regional Bell Operating Company (RBOC) was a corporate entity created as result of the antitrust lawsuit by the United States Department of Justice against the Western Electric Company and American Telephone and Telegraph Company (AT&T) in 1949 and a suit in 1974 against AT&T (United States v. AT&T). The suits were settled in the Modification of Final Judgment in August 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.

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.

A "Baby Bell" is a local telephone company in the United States that was in existence at the time of the breakup of AT&T into the resulting Regional Bell Operating Companies (RBOCs). Sometimes also referred to as an "ILEC" (Incumbent Local Exchange Carrier) they were the former Bell System or Independent Telephone Company responsible for providing local telephone exchange services in a specified geographic area.

After the Modification of Final Judgment, the resulting Baby Bells were originally named:

Prior to 1984, AT&T Corp. also held investments in two smaller and otherwise independent companies, Cincinnati Bell and Southern New England Telephone (SNET). Following the 1984 breakup, these became fully independent as well. All nine local-exchange holding companies were assigned a share of the rights to the Bell trademark.

After divestiture, AT&T Corp. was prohibited from using the Bell name or logo (with the notable exception of AT&T's Bell Laboratories) and those trademarks which would be shared by the RBOCs and the two companies AT&T partially owned. Cincinnati Bell was the last RBOC to hold the "Bell" name, but it rebranded as Altafiber in March of 2022.

Additionally, Bell Canada, the former Bell Telephone Company of Canada (founded in 1880) and which started separating from the Bell System in 1956, and completely by 1975, continues to use the "Bell" trademarks, which it owns outright in Canada.