The Bell System divestiture, or the Breakup of AT&T, was initiated by the filing in 1974 by the U.S. Department of Justice of an antitrust lawsuit against AT&T. The case, United States v. AT&T, led to a settlement finalized on January 8, 1982, under which "Ma Bell" agreed to divest its local exchange service operating companies, in return for a chance to go into the computer business, AT&T Computer Systems. Effective January 1, 1984, AT&T's local operations were split into seven independent Regional Holding Companies, also known as Regional Bell Operating Companies (RBOCs), or "Baby Bells". Afterwards, AT&T, reduced in value by approximately 70%, continued to operate all of its long-distance services, although in the ensuing years it lost portions of its market share to competitors such as MCI and Sprint. And Verizon was one of the Bell renamed.