Two such strategies are worth looking at, with one important warning: neither is completely risk-free. Anyone who wants a higher profit in less time has to accept some risk, and it is important to understand that risk before placing a single bet. For converting odds into percentages, this tool can help.
Tactic No. 1 is betting on the correct score. The first step is to choose the match carefully, ideally one in which a low-scoring game is widely expected. Take, for example, the Champions League third qualifying round match between Astana and Celtic. The experts expected few goals, so the assumption is that the home team will score no more than two goals and the visitors no more than one.
0-0 – 7.50 (13.33%); 0-1 – 7.50 (13.33%); 1-0 – 7.00 (14.29%); 1-1 – 6.00 (16.67%); 2-0 – 11.00 (9.09%); 2-1 – 10.00 (10%). The percentages add up to 67.73%. This means that if the match ends with one of these correct scores, the bettor makes a profit of 32.27% of the total stake.
Because this type of betting carries risk, the tactic is best spread across several matches to limit losses after an unlucky result. Its advantage is that there is no need to open accounts with other bookmakers: a single bookmaker is enough, which saves a lot of effort.
The second, bolder approach is to combine matches. This can earn considerably more, because the percentages can be summed, but it is vital not to miss any of the combinations, because a single uncovered outcome can wipe out the profit.
In the end, the decision rests with each bettor: these are bets for the brave, and they come with no guarantees. Good luck is part of the equation.
How the Astana match ended
The first leg of the third qualifying round tie was played at the Astana Arena on 27 July 2016 and finished 1-1. Yuri Logvinenko scored for Astana and Leigh Griffiths equalised for Celtic. A 1-1 draw was one of the six scores in the example, so the low-scoring assumption held on that occasion. Celtic won the return leg 2-1 at Celtic Park on 3 August 2016, with Moussa Dembélé scoring a penalty in stoppage time, and went through 3-2 on aggregate.
Implied probability and the bookmaker's margin
The percentages in the example come from a simple conversion: the implied probability of decimal odds is 1 divided by the odds, so odds of 7.50 correspond to 13.33% and odds of 6.00 to 16.67%. Across all the outcomes of a single market, a bookmaker's implied probabilities normally add up to more than 100%, and the excess is the bookmaker's margin, often called the overround. A classic arbitrage exists only when the best available odds for every mutually exclusive outcome add up to less than 100%, which usually means combining prices from several bookmakers.
The correct-score tactic works differently. The six scores do not cover every possible result, so their total of 67.73% is not a guaranteed margin but a wager that the match will stay within a narrow range. Any other score, such as 0-2 or 3-0, loses the whole stake.
How bookmakers respond to arbitrage
Bookmakers generally take an unfavourable view of arbitrage betting and tend to detect it quickly. Accounts identified as arbitrage accounts commonly have their maximum stakes reduced sharply, and some are closed altogether. In the past, half of an arbitrage bet could even be cancelled, which turns a supposedly risk-free position into an ordinary bet on a single outcome. Margins are also thin: the great majority of genuine arbitrage opportunities return less than 1.2 per cent of the total stake, which is why riskier tactics such as the two described here appeal to some bettors in the first place.
Questions people ask
What is arbitrage betting?
Arbitrage betting means backing every possible outcome of an event at odds whose implied probabilities add up to less than 100%. Covering all outcomes in that way locks in a small profit whatever the result, usually by using prices from several bookmakers.
How are odds converted into implied probabilities?
The implied probability of decimal odds is 1 divided by the odds. Odds of 7.50 therefore correspond to 13.33%, and odds of 6.00 to 16.67%.
Is correct-score betting risk-free?
No. Backing a handful of correct scores covers only part of the possible results, so any other score loses the whole stake. It is a bet on a low-scoring match rather than a true arbitrage.
How do bookmakers treat arbitrage bettors?
Bookmakers generally take an unfavourable view of arbitrage betting. Accounts identified as arbitrage accounts commonly have their maximum stakes reduced sharply, and some are closed.