المدربA bookmaker is a firm that quotes odds on the outcomes of an event and takes bets against them as the counterparty. The implied probability of decimal odds is . The overround of a book is the amount by which its implied probabilities over all outcomes exceed one: the bookmaker’s margin.
| Method | favourite (1.50) | middle (4.00) | longshot (7.00) |
|---|---|---|---|
| Implied, with margin | 66.67 | 25.00 | 14.29 |
| Multiplicative | 62.92 | 23.60 | 13.48 |
| Additive | 64.68 | 23.02 | 12.30 |
| Power | 64.82 | 22.71 | 12.48 |
| Shin () | 64.23 | 23.15 | 12.62 |