'The Super Bowl of boxing': How Vegas made Mayweather-McGregor odds

The best of Mayweather-McGregor world tour (1:37)

Four cities and three countries over four days. Floyd Mayweather and Conor McGregor traded verbal jabs from one city to the next. (1:37)

On Feb. 16, nearly four months before the Floyd Mayweather-Conor McGregor fight was made official, iconic bookmaker Jimmy Vaccaro and the oddsmaking crew at the South Point sportsbook in Las Vegas opened Mayweather as a massive -2,700 (1-27) favorite over McGregor. The last time Vaccaro made a fighter with those odds, he ended up making international news, and receiving a call from Steve Wynn, his boss at the time.

Flash back to 1990: Vaccaro was head of the sportsbook at the Mirage, a new hot spot on the Strip owned by Wynn. It was the only book in town with odds up on a seemingly lopsided fight in Tokyo between undefeated heavyweight juggernaut Mike Tyson and virtual no-name Buster Douglas.

A prominent Las Vegas odds service considered the bout basically an exhibition and advised its bookmaking clients not to even bother taking bets on it because Tyson was too big of a favorite; generating any sort of two-way action could be an issue. Vaccaro went for it anyway, opening Tyson as a -2,700 favorite.

Big bettors didn't flinch at the giant price on Tyson. Vaccaro inched the odds up as an array of large bets showed up on the champ: $54,000 to win $2,000, $96,000 to win $3,000 and, two days before the fight, $126,000 to win $3,000. The largest wager on Douglas was $1,500 at 37-1.

The odds on Tyson peaked at -4,200, an almost unthinkable price for a fight, but one that was required to attract any kind of money on Douglas. By the time the bell rang, Vaccaro had done his job, divvying up the estimated $1.8 million bet on the fight at the Mirage and putting his book in a no-lose position. They'd win a few thousand dollars if Tyson won and just over $100,000 if Douglas somehow pulled off the stunning upset.

"We were in a good spot," Vaccaro recalled.

Douglas shocked the world, knocking out Tyson in the 10th round in one of the largest upsets in sports history and delivering a solid decision for the Mirage sportsbook. The publicity, though, was worth much more.

In the early morning hours the Monday after the fight, Vaccaro's phone began ringing. Interview requests were pouring in, wanting to talk to the only Las Vegas bookmaker with odds on the fight. Vaccaro spent his morning and early afternoon appearing on national TV, on shows like "Good Morning America" and "Today," and speaking to newspaper reporters from around the globe. Then, he got the call from Wynn and headed up to the boss' office.

As he rode up the elevator, Vaccaro wondered whether he had said something wrong on TV and was in trouble.

"I walked in and he was sitting there smiling and laughing," Vaccaro said of the trip to Wynn's office. "He looked up at me and said, 'I don't know what the hell you did back there, but just keep doing it.'"

Twenty-seven years after Tyson-Douglas, Vaccaro is booking another seemingly lopsided fight -- Mayweather-McGregor on Aug. 26 -- only this time the odds are moving in the opposite direction.

Mayweather (49-0), nearly four weeks before a fight against a challenger with no professional boxing experience, is only around a -600 favorite at most shops. And the amount of money on the underdog McGregor is, as one bookmaker put it, "mind-boggling."

"This should be the easiest fight that any bookmaker's ever booked," Vaccaro quipped. "The general public is much more involved these days, and you know their hole cards. They're going to bet the big dog, and you'll know closer to the fight what number the big guys are salivating to lay."

When Las Vegas sportsbooks first started going through the process of setting the odds in February, they had no idea that they were creating a price on a fight that is setting up to be the most heavily bet bout ever.

Here is how Las Vegas bookmakers set those odds and how they are reacting to all of the betting action on McGregor so far.

Setting the odds

In February, buzz began to intensify about the possibility of Mayweather, the undefeated boxing champion, coming out of retirement to take on the flamboyant UFC star McGregor.

The matchup seemed unrealistic to some, and many doubted the two mega-personalities from competing sports would ever be able to come to an agreement. Still, there was clearly interest in the matchup, enough that oddsmakers at the Westgate SuperBook decided to throw around potential prices in the office behind the sportsbook counter.

They didn't break down punching statistics or analyze the speed and elusiveness of the fighters. They didn't scour the internet, looking for any video of McGregor boxing, or sneak a peek at Mayweather to see how much the 40-year-old had been enjoying retired life, either. Instead, they simply tried to predict how much would be bet on the fight and what percentage of the betting public would automatically gravitate toward McGregor, who would undoubtedly be a giant underdog.

That brief meeting behind the counter was all it took for the sportsbook to open odds on the fight on Feb. 16. They settled on Mayweather -2,500, although some thought -5,000 was more appropriate. McGregor opened as an 11-1 (+1,100) underdog.

"We knew there'd be some interest in McGregor," Jay Kornegay, vice president of Westgate race and sports, told ESPN in mid-July, "but the skill set, in a boxing match only, was so lopsided that we didn't think we were going to be able to make it high enough.

"You make a number based on what type of money and flow of money that you would expect at the counters. It's not necessarily the true odds; it's just reflective of the betting patterns that we expect to see. Since we opened [minus] 2,500 and it's now down to [minus] 700 ... that's how close we were."

Many sportsbooks waited until the fight was made official on June 14 before posting odds and still were surprised by the volume of early support for McGregor. A month before the fight, 85 percent of the money that had been bet on the winner at William Hill's sportsbooks was on McGregor, including a trio of $50,000 bets on the underdog placed by the same customer on July 24 that could result in a $662,500 profit. The early lopsided action had William Hill facing potentially its biggest decision in the company's five-year history in Nevada.

"It's mind-boggling the money McGregor has drawn so far," William Hill U.S. director of trading Nick Bogdanovich told ESPN on Sunday.

"There's no rocket science to it," Bill Sattler, the director of specialty games for Caesars Entertainment, told ESPN. "You just put something out there and go with it. We're trying to figure out how the public is going to bet this and not really sticking our necks too far out. We put something out there that is probably lower than what it realistically should be, and it's been running. It's [been] all McGregor at this point."

Bookmakers for MGM Resorts took a similar approach to their counterparts at the Westgate after the fight was announced, focusing more on how much they expected to be bet on the fight than the ability of Mayweather and McGregor.

"If there's a significant edge in skill and ability, that immediately prices the fight above five dollars [-500]," said Jay Rood, vice president of MGM Race and Sports Books. "If there's anticipation of a good handle, then it can circulate north of seven [-700] or eight dollars [-800]."

From one sportsbook to the next, up and down and on and off the Strip, the betting trends have been nearly identical -- thousands of bets on McGregor, with only a handful on Mayweather. And that has Las Vegas bookmakers currently sweating a bit, because their liability is currently quite lopsided.

Managing the liability

With the bets now flowing in, sportsbooks are wondering how much big money on Mayweather they can count on in the final weeks leading up to the fight. In the meantime, the money on McGregor hasn't slowed; in fact, it has intensified over the past few weeks, leaving bookmakers with a decision about how much liability their bosses are willing to endure.

"We could be in a position on the fight, for example, where we can lose several million and only win a few hundred thousand," said Jason Simbal, vice president of risk for Las Vegas sportsbook operator CG Technology. "That is not the scenario any sportsbook really wants to be in."

Some sportsbook directors told ESPN that they've already heard from their casino bosses, who were concerned about the liability building up on McGregor less than a month before the fight.

By mid-July, MGM's sportsbook had taken close to 1,800 bets on McGregor and less than 50 on Mayweather, according to Rood. One of the bets on Mayweather was close to six figures, but the book's liability remained on McGregor.

"The liability is quickly approaching seven figures," Rood told ESPN. "It's not making me nervous, but some guys on my team have said, 'How long are we going to let this go?'"

Rood's plan is not to panic. He hopes to keep the odds on Mayweather at -700 or higher for as long as possible and not offer too good of a price on the undefeated champion.

"[Floyd] is 49-0 for a reason, a perfect return on investment," Rood said. "So I don't want to give too much away on that side and end up needing McGregor for a big amount. If you go back at Floyd's average price the last 10 years, it's got to be north of six dollars [-600], and that's against the top competition in boxing. So now you're going to give him a subaverage price for a guy that's never really boxed in his life. I'm not willing to put Floyd Mayweather on a blue-light special. We're at -750, and I think that's a blue-light special."

Rooting for Mayweather a comfortable position to be in

Let's make something clear: Every bookmaker in Las Vegas wants to end up rooting for Mayweather to win a fight that's generating massive betting interest.

Several shops said the true odds of Mayweather winning are closer to -5,000 (1-50), but they're able to book the fight at a much lower price.

"I've said [McGregor] realistically could be 50-1," Westgate SuperBook assistant manager Jeff Sherman said, "and people have asked, 'Why don't you give me 50-1, then?' I tell them I don't need to, because you're already betting him at 5-1."

The Westgate expects twice as much money will be bet on Mayweather-McGregor than the amount wagered on Mayweather's fight against Manny Pacquiao, the most heavily bet fight in Westgate's history.

"This is the Super Bowl of boxing," said Sherman, one of several bookmakers who believe the true odds on Mayweather are much greater.

So while the exploding liability on McGregor may be causing concern for the casino bosses, the books know the odds are in their favor. Now, they're simply trying to gauge how many big bets on Mayweather to expect. Some shops are anticipating seven-figure wagers.

"I told my direct report that it's going to get ugly until fight week, and then we'll figure it out," Rood said. "I know I have probably three customers [with] the potential to play Mayweather really large. I'm just hoping that the Pacquiao decision [upset loss to underdog Jeff Horn] didn't spook anybody."

In the end, every sportsbook in Las Vegas is expecting to be rooting for Mayweather come Aug. 26 -- and they're just fine with that.

"We're comfortable needing Mayweather, let's just say that," Bogdanovich of William Hill said. "Right now, we're comfortable where we're at, but talk to me in another two weeks, when [the liability] keeps growing and growing and we might not be so comfortable. It's a crazy decision."