After the 1984 Bell System Divestiture, Ohio Bell became a subsidiary of Ameritech, one of the seven original Regional Bell Operating Companies. The Ohio Bell name continued to be used until January 1993, when Ameritech dropped all of its individual Bell Operating Company names in favor of its corporate name for marketing purposes, when it began doing business as Ameritech Ohio.
After SBC acquired Ameritech in 1999, it continued to retain the "Ameritech" brand until 2001, when Ohio Bell began doing business as SBC Ameritech Ohio. A year later, in 2002, SBC dropped the Ameritech name in favor of "SBC" as a national brand, resulting in the trade name of SBC Ohio. On January 15, 2006, after SBC's acquisition of AT&T, Ohio Bell's trade name was changed, again, to AT&T Ohio, a name which it continues to use today.