# Two books disagree on the same game Book A: Team X +105 -> 48.8% Book B: Team Y +110 -> 47.6% implied sum = 96.4% -> 3.6% locked margin # Stake in proportion to implied probability: stake_X = 48.8/96.4 × bankroll ; stake_Y = 47.6/96.4 × bankroll # Either result returns ~103.7% of total staked
Real arbs are usually 1–3%, short-lived, and operationally risky: one leg getting limited, voided, or repriced before the other fills turns an arb into an open position. Books also restrict accounts that only bet arbs.
The arb scanner computes cross-book implied sums continuously across the aggregated feed and lists markets under 1.0 with their margin. Freshness is the whole game here - an arb computed on stale prices is just a bad bet.