Generally speaking, Mayweather is a much bigger favorite for his fights than he is here. He was a -800 favorite last September for his rematch with Marcos Maidana, four months after their first fight, where Floyd was a -1000 favorite. For those fights, he was seen as four to five times more likely to win than he is against Pacquiao (57-5-2, 38 KO).
Mayweather (47-0, 26 KO) is listed between -215 and -300 on some major sportsbooks, having opened at -285. The American star has rarely even been seriously challenged over his 18 and a half year pro career, with but a handful of fights that have even been particularly competitive.
Manny opened as the underdog at +225, and is now available between +175 and +220. This is the first time Pacquiao has been the underdog in a fight since his bout with Oscar De La Hoya in December 2008, which turned out to be a Pacquiao romp.
Bovada currently has the fight listed at -300 to go the distance, with +230 odds that it will end before the final bell of the 12th round. This seems a fairly safe bet, considering the fighters' recent histories. Mayweather has only gone under 12 rounds twice in the last decade. In 2007, he stopped Ricky Hatton in the 10th round. In 2011, he beat Victor Ortiz with the infamous "sucker punch" in round four.
As with most truly major sporting events, there are all kinds of goofy prop bets you can make, too. Who will throw the first punch? Mayweather is at -125, Pacquiao at -105. Which hand will it be? -130 for left, EVEN odds for right. You can get 65/1 odds on there being five or more knockdowns in the fight.
And despite his vaunted power, Pacquiao has no stoppage wins since 2009, going 7-2 over that time. The only fight that went less than 12 was a sixth-round knockout loss to Juan Manuel Marquez in 2012, a fight that was aggressive on both sides, and saw Pacquiao walk himself into a crushing, perfectly timed right hand.
