Sportsbooks in the UK

A sportsbook maker aims to make a profit by evaluating the probabilities of each outcome in an event and then offering odds which, when combined, give him an overall edge, or what is commonly referred to as an "over-round".

To illustrate how this works, imagine the toss of a coin. This event has two possible outcomes - the coin can falls as heads or tails. The true probability of either outcome is therefore 50%. This equates to odds of 1/1 in fractional form or 2.0 in decimal (which always includes an extra 1 point to represent the returned stake of winning bets.). However, a sportsbook operator may offer odds of just 1.80 (4/5) about heads or tails. By doing this, he ensures an overall profit as long as the true odds of 50% heads and 50% tails are achieved in reality.

Of course, accurately evaluating the mathematical probability of a certain outcome taking place is never as easy in a sporting event as it is in the toss of a coin, so the aim of the serious sports bettor is to look for "value opportunities" where he thinks the sportsbook maker has been a little too generous with the odds he has offered. For example, if a bettor thinks that a particular boxer has a roughly 50% chance of success, and a certain sportsbook is offering odds of 3.0 (2/1) for that fighter, the bettor has found a good value betting opportunity.

With a sportsbook maker, a bet will generate a profit according to the odds offered, or it will lose the amount of money that has been staked. For example, if you stake £10 on a boxer at odds of 3.0 (2/1), you will get £30 back if the boxer wins, and you will lose your £10 if the boxer loses.

Because the profit of sportsbook makers is derived from the amount of money they keep from losing bets, they dislike winners with as much enthusiasm as left-wing politicians dislike their right-wing counterparts. So much so that, when a particular bettor is in the habit of winning regularly, the sportsbook maker will often close his account to avoid having to continue paying out.

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