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Jay Rood, MGM Resorts' VP of Race and Sports, was a guest on ESPN's "Mike & Mike" and discussed just how lopsided the betting action has been so far.
According to Rood, approximately 95% of the bets MGM has received so far have been on McGregor.
"Currently we have nearly 6,400 tickets written to Conor McGregor and about 280 tickets written on Mayweather," Rood told ESPN.
Likewise, according to the Westgate Las Vegas SuperBook, 95% of the bets they have received have also been on McGregor.
The reason most people are betting on McGregor is simple - there is little money to win betting on Mayweather.
According to Rood, some sportsbooks opened up with Mayweather as a -3000 favorite. At that price, a gambler would have to wager $3,000 just to win $100 or $30,000 to win $1,000. While many view Mayweather as a sure thing, that is still a lot of money to risk for little reward.
This creates a problem for the sportsbooks. With so many people betting on McGregor, they are at risk of losing a lot of money if he actually pulls off the upset. One estimate says the sportsbooks in Vegas would lose $48 million collectively if Mayweather loses.
To counter this, the sportsbooks are forced to keep the odds on Mayweather as low as possible in order to entice at least some bets on the favorite.
With just three days to go until the fight, Mayweather's odds are down to +550 to win. Now if somebody wanted to win $100, they would have to bet $550. If they wanted to win $1,000, they would have to risk $5,500.
The big winners here are the gamblers who were patient and waited to bet on Mayweather. While a bet on Mayweather still has a small reward, the risk is now much lower.
"We're looking for a little bit of Mayweather money to balance this out because we have a lot of liability on Conor," Rood said. "I have a bet that a guy wants to come out and lay $3 million on Mayweather, which wins close to $500,000."
But there is also a risk here for those who are still waiting to bet on Mayweather. That is, they don't want to wait too long.
According to Rood, 90% of the money being wagered comes in the last 36 hours before a fight. If a lot of that money goes on Mayweather to win - especially from the professional gamblers who typically bet much larger sums of money - the odds could reverse and start to swing higher again.