At this point, after months of over-the-top promotion, it's difficult to separate reality from hype for a fight that will almost certainly be the most-heavily bet boxing match ever.
Floyd Mayweather stoked the fire last week, telling late-night talk show host Jimmy Kimmel that he plans to bet on himself against Conor McGregor in Saturday's mega-bout in Las Vegas.
It's long been rumored that Mayweather bets on himself, either directly or through members of his entourage. UFC president Dana White told reporters in 2013 that Mayweather bets on himself, but some folks in Las Vegas aren't buying it.
"He's never bet on himself," a source with direct knowledge of Mayweather's betting history told ESPN. "He's very superstitious and that's the one thing he doesn't bet on, his own fights, ever. His friends and crew bet small on him, but he has never done it."
Will that change this week?
Mayweather, boxing's biggest star, remains one of the biggest sports bettors in Las Vegas, and in the past hasn't been shy about showing off his wagers -- the winning ones, at least.
For a while, a stretch from around 2012 through 2015, he regularly sprinkled in pictures of six- and seven-figure betting slips among photos of stacks of cash, gaudy jewelry and luxury cars on his Instagram and Twitter accounts:
• $1.1 million on Oregon -7.5 over Arizona State in October 2012.
• $800,000 on the Denver Broncos -7.5 over the New York Jets in October 2014.
• $200,000 on the Golden State Warriors over the Houston Rockets straight-up in May 2015.
The tickets Mayweather put up on social media were almost all winners and almost always posted after the fact. There was a running joke that not only was he unbeaten in the ring, but he was also undefeated at the betting window. ESPN has confirmed that Mayweather has indeed made losing bets at one time or another.
In May, he posted a picture of himself sitting in a jet with bundles of money, claiming that he bet on his buddy, point guard Isaiah Thomas, and the Boston Celtics against the Washington Wizards. Thomas scored 53 points, the Celtics won 129-119 in overtime and Mayweather ended up with cash on his lap. For the most part, however, the pictures of the actual betting slips have dissipated. It's not because he's stopped betting.
Mayweather still routinely bets five and six figures on NBA, NFL and college football and basketball. He doesn't bet baseball, sources said, and no one recalled him ever betting on a boxing or UFC match.
Mayweather's preferred bookmaker in Las Vegas is CG Technology, which operates the sportsbooks at The Venetian, The Cosmopolitan, Palms and several other casinos. It's believed that he currently bets exclusively with CG Technology.
Citing company policy that prohibits discussing individual customers, CG Technology declined comment for this story.
Mayweather and his crew bet most often at the CG Technology sportsbook at M Resort, a casino located roughly 12 miles off The Strip. They're not hard to pick out.
"They're the guys in the TMT hats (The Money Team associated with Mayweather), sitting in the VIP section," a source said.
Sources familiar with Mayweather's betting insist that he's not a complete square and, at times, has passed on games if he doesn't like the point spread. But, at the same time, competing bookmakers have courted Mayweather's action, which may be the most-telling detail about his level of success.
"They're lucky to have him," one Las Vegas bookmaker quipped with a chuckle.
Mayweather has been known to chase losing wagers by doubling up the size of his bets on later games and regularly gravitates to popular public favorites. In the past, those familiar with his day-to-day bets could almost predict which teams he was going to back during an NBA slate: The Miami Heat during the LeBron James years, the San Antonio Spurs, and Oklahoma City Thunder with Kevin Durant and Russell Westbrook were staples on Mayweather's past betting cards.
There was a period of time, around 2013 and 2014, in which Mayweather suddenly started betting more random games -- $50,000 on a Harvard basketball game or $100,000 on an odd first-half bet, for example. Strangely, Mayweather's bets during that time began mimicking some of the sharper accounts that were playing at CG Technology. Buzz began to build that someone was in his ear, telling him which teams to bet.
In 2013, Mayweather was spotted on a TV broadcast, sitting courtside for a Sacramento Kings game against the Dallas Mavericks. Isaiah Thomas was still with the Kings at the time and was seen interacting with Mayweather during the game. At halftime, a $50,000 bet on the favored Mavericks in the second half was placed from Mayweather's account. The Kings pulled away from Dallas in the third quarter, and the bet lost.
No ticket appeared on social media.
If he chooses to place a wager on himself, Mayweather won't be violating any rules.
Neither the Nevada Athletic Commission nor Nevada Gaming Control has regulations addressing the ability of contestants to bet on themselves to win a fight. The NAC "expects all contestants, licensees and other persons associated with unarmed combat to comply with all state and federal laws regarding contest wagers," a spokesperson told ESPN in a statement. If a fighter were to bet against themselves, however, federal law -- the Sports Bribery Act of 1964 -- would likely come into play, according to legal sources.
While apparently legal, betting on himself doesn't make much financial sense for Mayweather. As of Tuesday morning, he was around a -400 to -500 favorite to beat McGregor at sportsbooks around the world. At the best odds, Mayweather would need to bet $4 million just to win $1 million. ESPN business reporter Darren Rovell estimates Mayweather is in line to make $220 million on the fight.
"The guy's got $200 million he's trying to make on this fight," Chris Andrews, a veteran Las Vegas sportsbook director, now at the South Point casino, said. "What's an extra $150,000, $200,000 to him?"
On Friday, more money, £2.5 million ($3.2 million), was staked on Mayweather-McGregor on the United Kingdom betting exchange BetFair than any other day to this point. The flurry of action -- most of it on McGregor -- came in the wake of Nevada Athletic Commission's decision to allow the fighters to wear eight-ounce gloves. It also coincided with a tweet Mayweather sent out, informing followers that he would be "partying the entire week before my fight" as part of a promotion of his Las Vegas strip club "Girl Collection."
"I doubt Floyd's twitter messages mean much," said Art Manteris, vice president of race and sports for Station Casinos and longtime sportsbook director in Las Vegas. "He keeps really unusual hours normally and is seen around Las Vegas at all hours of the night. But, to my knowledge he doesn't drink, smoke or do drugs. He has never entered the ring unprepared as a professional, or in anything other than top shape in my opinion. Win or lose, it won't be because he is unprepared."
Mayweather's odds to win the fight reached a low point over the weekend in Las Vegas, as public bettors continued to flock toward McGregor, increasing the liability on the underdog that's already reached millions of dollars at multiple sportsbooks in Las Vegas.
"Don't forget, we had a guy bet us $880,000 on the favorite," Andrews of the South Point said. "And it's still being overpowered by the public. It's unbelievable."
The price on Mayweather dipped to -490 at CG Technology on Sunday, which was cheap enough to attract an additional six-figure bet on the favorite.
It was not placed by Mayweather, sources said.