A typical arbitrage sports betting scenario occurs when two or more bookkeepers have different predictions based on the same sporting event. The varying prices are either due to different opinions or as a result of an error. The idea is that you can beat the odds, making an overall profit, if you place a single bet on each possible outcome with different bookkeepers. Basically, it involves putting money on all potential results of a sports event.
Those in the know refer to a potential arbitrage betting situation as an ‘arb’, ‘surebet’, ‘overbroke’ or ‘underground’. An arb is only created when the predicted odds of at least two different betting companies are high enough and sufficiently different to allow the bettor to back opposing sides. In other words, there’s no use hedging your bets with the same bookie.
A bettor who engages in this practice is known as an ‘arber’. Sometimes referred to as scalping or surebetting, arbitrage betting is generally frowned upon by bookmakers. Bookie companies have been known to limit or even block the activities of alleged arbers. A common way to capitalize on an arb and fly under the bookmaker’s radar is for a ‘key man’ to delegate others to wager in his place.
Indeed, with increased access to the Internet, incidences of arbitrage betting have become more problematic for bookies. This is because information on betting-exchanges and odds comparisons are more accessible than ever. On the other hand, the Internet has also enabled bookies to keep odds inline with the industry, creating fewer arbing opportunities.
In most cases, arbs are about 2% but can be greater. Often arbitrage betting involves large sums of money. There are several mathematical formulas and arbitrage websites that can help you calculate the proportion of money you should place on each bet.
It is often claimed that sports arbitrage is risk-free because, by hedging your bets, you are guaranteed to make money, regardless of the outcome of the match/race/game. While there is always a degree of uncertainty and loss involved, the aim is for the profits to exceed the losses.