"Vig (overround), defined"

The vig — also called the overround or margin — is the amount by which a market's implied probabilities exceed 100%.

If the two sides of a match market imply 55% and 50%, the market sums to 105%. Those 5 percentage points are the vig. It is not a fee added on top; it is baked into every price, which is why reading odds naively overstates each outcome's chance.

Vig varies. Tighter markets carry less of it, thinner ones more. That variation is exactly why implied probabilities from two different markets cannot be compared until the margin has been removed from each.

Removing it is called de-vigging, and the result is the fair probability the market actually expresses.

EsportsOdds publishes a single de-vigged market line rather than raw prices. See the vig explained for the full method.