The company have taken several big-money bets, including one of pounds 50,000 for Tyson, but the vast majority are for up to pounds 100 and are going on Bruno.
Hills make Tyson 1-5 favourite with Bruno at 10-3, while rival company Ladbrokes currently have Bruno the 3-1 underdog with Tyson quoted at 2-9 to repeat his victory from the pair's first encounter.
Ian Wassell, of Ladbrokes said: "Frank is as popular in the betting shops as he is with the British public at large. We've taken bets of up to pounds 2,000 on Bruno and many thousands of pounds 5 and pounds 10 flutters.
"This is building up into the busiest betting fight ever and we expect over pounds 10m to be wagered across the betting industry. The previous record was for Tyson-Bruno I."
Ladbrokes are refusing to quote odds on Naseem Hamed retaining his World Boxing Organisation featherweight title tonight in Glasgow. "Naseem is so good the odds we would offer would make it impossible for people to win money on him in a betting shop because of the betting tax," Wassell explained.
Hamed's opponent, Said Lawal, of Nigeria, is quoted at 14-1 to win.Reuse content