Definition
Hold is the sportsbook’s built-in margin on a betting market. It is the percentage of total money bet that the book expects to keep if action is balanced across all outcomes.
For a market, first convert each price to implied probability, then add them together:
overround = sum of implied probabilities - 1
theoretical hold = overround / sum of implied probabilities
For American odds:
Negative odds: odds / (odds + 100) using the absolute value.
Positive odds: 100 / (odds + 100).
Worked Example
A point spread has both teams priced at -110.
Each side has implied probability:
110 / (110 + 100) = 0.5238, or 52.38%
Both sides together:
52.38% + 52.38% = 104.76%
The overround is:
104.76% - 100% = 4.76%
The theoretical hold is:
4.76% / 104.76% = 4.55%
If the book takes $110 on each side, it collects $220. The winning ticket returns $210 total: $110 stake plus $100 profit. The book keeps $10, which is 10 / 220 = 4.55%.
Why It Matters
Hold helps a bettor compare prices across sportsbooks. Lower hold means less margin to overcome before a projection edge can matter.