He's known as 'Money' Mayweather for a reason.
Floyd Mayweather attempted to place a $400,000 bet on himself to defeat Conor McGregor, in the hours before Saturday's fight.
According to ESPN, the 40-year-old arrived at a Las Vegas casino on Saturday afternoon,but was not allowed place the six-figure sum on himself.
The 50-0 fighter reportedly attempted to bet on winning the fight inside 9.5 rounds. The stoppage came 1:05 into the tenth round, meaning he would have won with 25 seconds to spare.
Speaking to ESPN after the fight, he revealed that after giving the money to a friend, the bet was still not allowed go through.
They didn't let me bet 400,000.
Earlier today, I went to go and bet 400,000 and they didn't let me bet at a casino that I went to, because I was the promoter.
They thought the fight was going to be set up. I'm not going to set up a fight for 400,000 when I'm making over 300 million.
I gave my friend 400,000 to go and bet. They would only let him bet 87,000.
Mayweather is known for his love of big-money bets on other sporting events, including college football and basketball games.
There are no laws in Nevada to forbid fighters or promoters from betting on fights they are taking part in.
With a nine-figure sum to add to his wallet from defeating McGregor, they little bit more he earned from the five-figure bet could be a drop in the ocean in Maywather's earnings.