Edge

Arbitrage betting (arbing) involves placing bets on all possible outcomes of an event across different bookmakers at odds that guarantee a profit regardless of the result. It exploits price discrepancies between books and is considered risk-free in theory.

A middle is a situation where you can bet both sides of a point spread or total at different bookmakers with overlapping ranges, creating a scenario where both bets can win. The downside is limited (you lose the vig on one side) while the upside can be substantial.

A value bet occurs when the odds offered by a bookmaker are higher than the true probability of the outcome. Consistently finding and placing value bets is the foundation of profitable sports betting. The edge may be small per bet but compounds over a large sample.

Sure bet is another term for arbitrage — a combination of bets across different bookmakers that guarantees a profit regardless of the outcome. The term emphasizes the risk-free nature of the strategy, though in practice factors like bet limits, voided bets, and account restrictions introduce operational risk.