What is the Market Overround?

Overrounds show you how competitive the odds are. The closer to 100%, the better the odds. It is calculated by converting the best odds on each selection into a % chance of winning. These percentage numbers are sometimes referred to as the ‘Hold' or 'Overround’, i.e. the margin included in the odds by those offering plays.

For example, if Team A are -126, that means the person offering the play is giving themselves a 55.75% chance of winning (126 / 226). If Team B are +116, the person offering that play is giving themselves a 46.3% chance of winning (100 / 216). The percentage you’d see is the sum of those two numbers, 102.05%. -124 +118 would of course be better value and the % number would therefore be closer to 100%. Here’s the calculation: (124 / 224) + (100 / 218) = 101.23%.

Note that the way to calculate the % chance for negative odds is ‘the odds’ divided by ‘100 plus the odds' whereas for positive odds it is ‘100’ divided by ‘100 plus the odds'.