According to Betfair, Who Won the Iowa Caucus?According to Betfair, Marco Rubio won the 2016 Iowa Caucus by a landslide. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to print (Opens in new window)Click to email a link to a friend (Opens in new window)