Sports arbitrage, explained.

One event, different prices

Sports arbitrage means covering every possible outcome of the same market at prices that produce a positive net result in the mathematical model. It is about the combined prices, not predicting the winner.

For decimal odds, add the reciprocal of each outcome’s odds. A sum below 1 indicates a possible arbitrage before fees, rounding and execution issues.

A two-outcome example

Suppose two operators offer decimal odds of 2.10 on opposite outcomes. The market must genuinely have only those two outcomes, with matching settlement rules.

The model commits $100 and returns $105 whichever outcome wins: a $5 net result before any fees. These are illustrative odds, not a current betting opportunity.

Why execution matters

Both wagers have to be accepted at the intended prices. A price change, partial acceptance, stake limit, voided wager, commission or different overtime rules can break the calculation. An event that appears identical can still be settled differently.

Never treat an unaccepted second wager as secured. The maths describes a fully matched position; it cannot guarantee that the position will be available or remain valid.

A useful habit

Write down the exact event, market, settlement rules, odds, fees and accepted amounts. Compare the final outcome-by-outcome returns. If one scenario remains uncovered, the position is not a complete arbitrage.

This is an educational example, not a live feed or an instruction to place a wager.