How Bets are matched at a Betting Exchanges

A bet is not actually made until it is matched. If someone backs a horse £100 at 5.00 and someone is willing to lay those odds then the bet is matched. A bet may be matched by one or more people. For example, someone may match £60 worth of the bet and another person £40. Once bets are matched they cannot be cancelled.
The bets are held in a queue and are dealt with in the order in which they arrive at the site’s server. The queue works on a first come first-served basis, so it pays to place bets early in order to get a match. Any bets that are not matched by the start of the race will be void and the stakes refunded. The better the odds that you offer, the more likely you are to get a match.

Partial matching

Suppose you want to stake £10 on Dobbin at odds of 10.5. On the betting screen, you would enter odds of 10.5 and your stake of £10. £2 of your bet would be matched and the remaining £8 would be unmatched. On the lay side of the odds, 10.5 £8 would appear, with the current best price of 11 £266 moving one place to the right. Once your 10.5 £8 stake has been matched it will disappear from the odds screen.

The odds for Dobbin are refreshed in the table:

9.8       10           Dobbin                10.5       11       11.5
£54      £497                                  £8         £266    £200


If someone decides to lay these odds, that is bet £8 at 10, your bet would be matched and the betting screen will now be as

9.8       10           Dobbin                11       11.5       13.5
£54      £497                                 £266    £200       £8

On your personal account screen it would show that your £10 bet at odds of 10.5 has been matched. Now that your bet has been matched it can no longer be cancelled. 

Ordering odds

If the odds that you want are not currently available you can place an order for them. Your bet may be fully matched, partially matched or unmatched. If your order is matched then the bet is made. If your order is not matched by the time of the off then your bet is void. There is a limit to the odds than can be ordered. Odds lower than 1.01 are not allowed odds over 1000 not allowed.

If, for example, odds of 4.5 are offered for a horse to win and you want odds of at least 5.0 and want to stake £100, then you place an order for odds of 5.0 and offer a stake of £100. If another person is willing to lay at these odds, that is bet that the horse will lose, then your bet is matched. Your bet can be matched up to your maximum stake of £100. Your bet will be made if someone is prepared to stake £500 that the horse will lose. That is enough to payout your winnings. What may happen is that your bet is matched with several people’s lay bets. For example, one lay bet of £10, one lay bet of £20 and one lay bet of £50. If by the off these are the only three matches then you will have a bet of £80 at odds of 5.0. The additional £20 will be void. If the horse wins, you will receive £420, where £400 is your winnings and £20 is void. Commission will be calculated on the net winnings of £320. At 5 per cent, the commission will be £16. You will therefore receive £404.

If you offer odds to other betters you will need to make your odds competitive in order to get a match.

To stop ridiculous odds being offered like 1000/1 when the current odds are 5/1, an order can usually only be placed within a certain increment of the current best price. You will need to consult the exchange rules for the increments.

You could bet £2 at odds of 10.5 and place an order for £8 at odds of 10.5. Your £8 bet would only be valid if someone else is willing to match it.


9.8       10       10.5       Dobbin          11       11.5       13.5
£54      £497    £2                             £266    £200       £8
If you took this option the 10.5 odds would dissapear from the highlighted column to be replaced by the odds of 10. On the lay side, your odds of 10.5 with £8 underneath would appear in the highlighted column where it will remain until somone matches it, that is, decides they want to stake £8 at a price of 10.5 that the horse will loose.
9.8       10            Dobbin          10.5    11       11.5       13.5
£54      £497                            £8       £266    £200       £8
Best odds
If you place a bet at the odds of 6.0 and odds of 6.5 are available then your bet will be matched at these odds as they are better then 6.0. They will not be matched with odds of 5.5 as these are worse odds.

Back all and lay all

The betting screen also gives you the opportunity to back all the runners.  This is backing the entire field to win, that is all the horses that are running. Lay all is laying the entire field, that is all the horses to lose.


Official result

All winning bets are settled according to the official result at the time of the "weigh-in". This means that if, for example, a horse is later disqualified due to a positive drug test, the result at the "weigh-in" still counts.



If a horse is a non-runner, all unmatched and matched bets on the horse are void. If the race is a walkover (there is only one runner) all bets are void on that race. If a horse is withdrawn from a race once a market has been formed then depending on the price of the withdrawn horse, the prices on the remaining horses may be lowered. You are advised to check the betting exchange’s rules.

The amount that the price is reduced by is a percentage and called the reduction factor. It is based on the rule 4 system that bookmakers use. Prior to betting on a race, each horse is given a reduction factor based on the exchange’s estimates of each horse’s chance of winning. Unmatched bets to lay will be cancelled.

In the win market, reductions are made on the whole odds. With a matched bet at odds of 6.00 and a horse with a reduction factor of 20 per cent, your odds will be reduced by 20 per cent and become odds of 4.80.

In a place market, the reduction factor is made to the win portion of the odds. With a reduction factor of 25 per cent, the win portion of the odds will be reduced 25 per cent, odds of 8 would become 6.25.

For a price of 8, the win portion is the price minus the stake 8-1=7
8 – 1.75 = 6.25


Dead heat
In the event of a dead heat, the odds are divided by the number of declared winners for the market. Suppose two horses dead heat for first place and you have backed one of the winners at a price of 5. You will be paid out at a price of 2.5.