Overround

The sum of every implied probability on a board, expressed as a percentage. A fair market would total 100%; anything above that is the bookmaker's margin. It is the same quantity as hold, and it is the number worth watching on an outright field, where 20 or more runners can push the book well past 120% and quietly erode the value of every price on the board.

• Hold — The percentage a sportsbook's two-sided prices add up to above 100% — its built-in margin. Lower hold is a better deal.
• Vig / Juice — The bookmaker's built-in margin — the reason both sides of a market aren't priced at +100. Strip it from both sides to get the no-vig fair price.
• Outright — A bet on who wins from a field of many competitors — one price per entrant, only one winner.