The proceeds will be given to charities in Las Vegas and Los Angeles if Mayweather wins. The wealthy entrepreneurs and former Sacramento Kings reportedly revealed that they placed the bet to the Associated Press on Sunday.
Mayweather and Gavin Maloof live in the same neighborhood. If Mayweather wins, the brothers will collect a total of $1.04 million.
With the Mayweather-McGregor fight two weeks away, one Las Vegas casino received the largest known bet on the bout so far.