One of the more popular proposition bets in boxing is the Over/Under bet otherwise known as the Total round's wager. Over/Under bets operate on the moneyline system and often provide bettors with a more valuable option than a straight up wager on who wins or loses the bout.
The reason for this is that the majority of fights are mismatches with lopsided odds that provide no value. For example when Floyd Mayweather fought Conor McGregor the odds had Mayweather as a -1100 moneyline favorite to win the bout over McGregor. While most experts and fans expected Mayweather to win easily it was still a dicey proposition to wager $1100 to profit a measly $100 on a Mayweather win. For this reason most people wagered on the Over/Under total rounds proposition which was set at 9.5 Rounds with a -200 moneyline.
It must be understood that 9.5 means that a fight must go over 1:30 into the 9th round to win as an Over.
If the Over/Under is 9.5 Rounds and the boxing fight ends at 1:29 into the 9th round this would cash in an Under win. It must be noted that Over/Under bets range from 1.5 rounds to 11.5 rounds and also come attached with moneylines. This means that fight Over/Under bets range from 1:30 of the 1st round (1.5) to 1:30 of the 12th round (11.5).
Most moneylines open in the -110 to -150 range but can go as high as -800. For example, in the 1980’s heavyweight champion Mike Tyson knocked almost all of his opponents in the 1st round. Because of this the oddsmakers would list the Over/Under at 1.5 rounds with the Under -150 expecting the bout to end in 1:30 or less of the 1st round.
On the opposite side of the spectrum, Floyd Mayweather’s fights were almost exclusively listed at 11.5 rounds with the moneyline price tag as high as -800 on the Over.
Prior to fighting Conor McGregor the brittle handed Mayweather for all of his greatness had only had 1 fight go Under 11.5 rounds in his previous 11 fights. It should be noted that the one fight that Mayweather managed to go Under the 11.5 mark was when he sucker punched Victor Ortiz to score a cheap knockout win.