Remember that guy from Back to the Future, who made a fortune on betting, because he stole that sports results book and used it in the “past”? Probably you also dreamt of a risk free betting. As we know, travel in time is a little hard at the moment, but there is a certain betting strategy that may bring you some risk-free bets.
It is called “Forks strategy”. There may be some other names for it (arbitrage, sure bets, holes etc), but all of them are about the same.
The concept of the strategy is the “fork” where the fork prongs symbolise the odds in different sportsbooks. The idea is to make a few bets on the same event – one on every “prong” and win money with only one winning bet. How? Mathematics and analysis.
Let’s look at a simple example to get everything clear. There is a basketball match between Houston Rockets and Golden State Warriors. Let’s suppose we look at the odds for the winning team, so we only have two possible outcomes here – win/lose.
You check the odds for the game, let’s say, in Bwin, and the odds are:
Rockets – Warriors 1.70/2.10
Let’s combine the probabilities here by dividing 1 by the odds: 1/1.70 + 1/2.10 = 1.06. All sportbooks will give you a number bigger than 1 in order to earn – those 0.06 decimal is a profit of a bookmaker. Of course they want to win on your bets not less than you do. This is why you will always have those interesting bets in different sportsbooks.
The next question is the size of bets to make. If all odds are the same, the bet sizes should also be the same, but this will hardly happen, so you will need a formula for this.
Result odd / sum of all odds
Let’s take an example – 3 odds for the same match from 3 different sources.
1.83 / 17.00 / 3.00
Let’s check if this is a sure bet or not. The sum of probabilities should be less than 1.
(1/1.83) + (1/17) + (1/3) = 0.939 – this one is a fork.
Then we find out the bet size. Let’s say you have a budget of $100.
For the first odd: (1/1.83) / 0.939 = 58.19% – $58.19
For the second odd: (1/17) / 0.939 = 6.26% – $6.26
For the third odd: (1/3) / 0.939 = 35.5% – $35.5
The potential wins are as follows: $106.49, $106.42, $106.5. We invested a budget of $100 and will definitely get at least $6.42 profit because we’ve found a sure bet!
Again, this does not happen very often, but there are numerous online services that publish the sure bets or fork bets regularly for free or for small charge.