WIS went on the air in 1930 from Columbia, S.C.  It was the last U.S. broadcast station to be issued a previously unused call sign with three call letters instead of four. Liberty Life Insurance Company purchased the station shortly after it signed on. WIS became an NBC affiliate in 1931.

WIS-TV signed on in 1953.  The two stations operated under a new Liberty subsidiary, The Broadcasting Company of the South, which later became Cosmos Broadcasting Corporation.

Cosmos sold WIS-AM in 1986.  New owners changed the call letters to WVOC and adopted a news/talk format.  It flipped to a sports format in 2011 and became WXBT-AM in 2012.  The station returned to a news/talk format in 2014 and reclaimed its WVOC call letters.  As of 2015, iHeartMedia owns WVOC.

Although the sale of WIS-AM in 1986 was part of Cosmos Broadcasting’s exit from the radio business, it wasn’t the end of the “WIS” brand on Columbia radio.  The company, which still owned WIS-TV, entered an agreement with WOMG-AM in 1995.  The station became all-news WISW, branded “WIS,” which carried AP Radio newscasts and audio simulcasts of WIS-TV newscasts.  

Ratings did not materialize and WISW went to an adult standards format in the early 2000s.  It flipped back to news/talk in 2002.  In 2014, it became a sports station and dropped the “WIS Radio” branding.  As of 2015, Cumulus Media owns the station, which calls itself “NBC Sports Radio AM 1320.”

Sources: Wikipedia (WVOC, WISW)