Vig, Overround and Hold: Three Ways to Measure One Sportsbook Margin, and Why State Reports Differ
A standard −110/−110 line has an overround of 4.76%, but a sportsbook that takes equal money on both sides keeps 4.55% of what was bet, not 4.76%. Both numbers describe the same margin measured against different bases. State revenue reports then publish a third figure, actual hold, which can land far from either in any given month. This piece separates the three. Concept: one margin, three bases Overround is the amount by which a market's implied probabilities exceed 100%. It is measured against probability. Theoretical hold is the share of total money wagered that the book expects to keep if the line is priced as posted. It is measured against handle, the total amount bet. Actual hold , the figure in state revenue reports, is what the book kept after results were settled, divided by handle. It is measured against what actually happened. The first two are fixed by the price. The third depends on outcomes and on which bets customers chose. Formula For each side, implied pr...