Hold (sportsbook hold percentage)
The share of total handle a book expects to keep on balanced action: overround divided by the sum of implied probabilities.
Hold and overround describe the same margin from two angles. Overround is how far the implied probabilities exceed 100%; hold is that excess as a fraction of the total, which is what the book actually keeps if bettors split evenly. A 104.8% overround is a 4.5% hold.
Published 'hold' figures from state regulators are realized results that include one-sided action and luck; the number ArbMonster reports is the theoretical hold built into the prices at the moment they were quoted, which is what matters for arbitrage math.
Measured on ArbMonster: Sportsbook hold rankings
Related terms: Vig · Implied probability · No-vig odds