Vig (Vigorish)

Vig (short for "vigorish," also called juice, hold, margin, or overround) is the implicit commission baked into sportsbook odds. When a book lists Lakers -110 / Celtics -110, those prices imply a combined probability of about 105% — the extra 5% is the book's margin.

The book doesn't take a separate fee; the margin is hidden in the prices themselves. You only see it by adding up the implied probabilities of every outcome in a market: if they sum to more than 100%, the difference is vig.

Vig varies by market type. Game lines (moneyline, spread, total) usually carry 4-5% vig because of the high volume and tight competition between books. Player props can be 8-12%. Outright futures (championship winner, MVP) often run 15-25% because the field is wide and the book takes on more risk.

Why this matters: any sportsbook price you compare against another reference (Kalshi, another book, your own model) must be de-vigged first, otherwise you're comparing apples to oranges. The book's vig is not a probability — it's a fee.