The Regional Bell operating companies (RBOC) are the result of the United States antitrust action against AT&T in 1983. After the Modification of Final Judgment, the resulting Baby Bells were originally:
- Ameritech
- Bell Atlantic
- BellSouth
- NYNEX
- Pacific Bell
- Southwestern Bell
- US WEST
- In 1998, Southwestern Bell changed its name to SBC Communications and acquired Pacific Bell and Ameritech.
- In 1997, NYNEX was acquired by Bell Atlantic, which later, in 2000, merged with GTE to form Verizon.
- In 2000, US WEST was merged into Qwest, a fiber optic company.
- BellSouth is the only RBOC that remains as originally conceived, and is the only company that still carries the "Bell" name. BellSouth still uses the last Bell logo, designed in 1969.