Hold (market vig) calculator
How much margin a market carries: the hold of one book's prices or of the best price on each side across books, the band it falls in, and the price that would make it fair.
Inputs
Result
updates as you typeRun this math on every line, automatically
The Low Hold screen ranks the cheapest two-way markets across your books, at net prices after fees.
How it works
Hold is how far a market's implied probabilities add up past 100%:
hold = Σ 1/di − 1
book margin on balanced action = 1 − 1/Σ(1/di)
Use one book's prices to see its margin, or the best price on each side across books to see the market's combined hold. Bands, as in our tools: below 0% is an arbitrage, 0–1% near-arb, 1–2% low hold, 2% and up standard. Low-hold markets are where promo conversions and hedges lose the least.
Worked example
Two prices at −110 each imply 52.38% + 52.38% = 104.76%, a 4.76% hold. A book with balanced action on both sides keeps 1 − 1/1.0476 = 4.55% of the money.
| Prices | Hold | Band |
|---|---|---|
| −110 / −110 | 4.76% | standard |
| −115 / −105 | 4.71% | standard |
| −105 / −105 | 2.44% | standard |
| +100 / −102 | 0.50% | near-arb |
| −108 / +102 | 1.43% | low |
| +105 / +100 | -1.22% | arb |
Things to watch
- Hold is not edge. A low-hold market is cheap to play both sides of; it does not make either side +EV.
- Different books, different rules. A combined hold across books only holds if both settle the same way.