It could be a great, or a terrible time to be a bookie in Las Vegas, depending on how the "fight of the century" goes on Saturday night.
If brash UFC champion Conor McGregor manages to score the upset to end all upsets against undefeated boxing legend Floyd Mayweather Jr. early on in the fight, bookmakers in Sin City will lose million of dollars in what would be the biggest single event lost in the history of sports betting. As if it didn't seem like there was enough riding on this fight already.
This potential loss comes as a result of so many McGregor fans literally betting with such frequency on the Irishman that even a late surge of money bet on Floyd might not be enough to balance the books. This isn't professional gamblers putting big money on one fighter. It's grassroots betting. And if it pays off, the bookies could wind up paying.
"I'm OK now," said William Hill oddsmaker Nick Bogdanovich. "But you might want to have a heart monitor on me when the bell rings and Conor starts throwing wild lefts."
When betting opened, Mayweather began as the favorite with odds that he won at 11-1. However, those odds have shrunk to 5-1, or even less on some of the books. That's largely down to the unpredictability of the fight. Many who have gambled feel like anything could happen.
"There's plenty of money on a guy who has never been in a boxing ring," said Jimmy Vaccaro, oddsmaker at the South Point resort. "It's uncharted waters and that's what makes it so interesting."
There are quite a few books that have more money wagered on Mayweather, but that's likely because a Mayweather win pays out less than a McGregor win, and therefore more money must be bet.
"We're just kind of going along balancing and are in great shape win on both sides, no matter who wins," said Johnny Avello, oddsmaker at the Wynn resort. "A lot of guys are putting down $125,000 or so to win whatever on Mayweather so we're high on him now."
Bettors however, will likely come out fine regardless of the outcome. the extra betting on football that comes with the McGregor bettors will be a decent cushion to fall back on if necessary.
"We don't mind a large decision on a big spectacle like this," Bogdanovich said. "It gets people in our books."
(The Associated Press contributed to this report)