What is Rule 4 in horse racing, and how does the deduction work?

What Rule 4 means for your bet

Rule 4 is the name racing gives to a deduction from your winnings when a horse is withdrawn from a race after you have placed a bet. It applies once the final declarations have been made, which is the point when the list of runners is confirmed, and before the race is started. If your own horse is the one that comes out, there is no deduction: the bet is void and your stake is returned. Rule 4 is about the other horses, the ones still running.

It is a deduction from winnings and only from winnings. You keep your stake in full on a winning bet. If your horse loses, there is nothing to deduct from, and the rule changes nothing. That is why a Rule 4 notice on a bet slip can feel like an arbitrary penalty when the horse wins: the stake comes back, and the profit is simply smaller than the price you saw when you placed it.

Why the deduction exists

A bookmaker prices every runner in a race on the assumption that all of them will start. Each price carries a view of how likely that horse is to win, and the views of all runners add up to a little over 100 per cent, with the surplus being the bookmaker’s margin. When a horse is withdrawn, its share of the market goes to the others. The horses that remain are now a little more likely to win than the prices you took allowed for, and a bet at the old price is worth more than it was when you struck it.

The deduction puts that right. The shorter the price of the withdrawn horse, the bigger its share of the market, and so the bigger the adjustment. The scale roughly follows the chance that the market gave the horse: a horse at 1/9 was priced as a nine-in-ten chance and carries a 90p deduction, a horse at 4/1 was about a one-in-five chance and carries 20p, and a horse at 10/1 or longer carries 5p. It is an approximation and not a calculation made for each race, and it is the same for everyone who has a fixed-price bet on that race.

How a deduction changes what you are paid

Work out the winnings first and take the deduction from them. Suppose you back a horse at 3/1 with £20 to win. The winnings would be £60 and the total return £80. If a horse at 4/1 is withdrawn, the scale gives 20p in the pound. Twenty pence in every pound of £60 is £12, so the winnings are £48 and the return is £68. The stake of £20 is untouched.

The table shows why the identity of the withdrawn horse matters more than the fact of a withdrawal. A long-priced outsider that comes out costs you £3 of profit. A hot favourite at 1/2 costs you £39. Before a big race, it is worth looking at the head of the market on the morning, because a late withdrawal of one of the first three in the betting is the case that changes your bet most. Our Rule 4 calculator does the sums for any stake, price and withdrawn horse, and our Rule 4 explainer shows the same arithmetic one step at a time.

The scale, and why bookmakers’ tables differ

The published scales, such as the one in the Racing Post’s bet calculator, run in bands from 90p in the pound for a withdrawn horse at 1/9 or shorter, through 40p around 6/4, 35p at 7/4, 20p at 4/1 and 10p at 9/1, to 5p at 10/1 and above. A bookmaker’s own terms give its table, and the edges of the bands can sit a price or so apart. One firm may put a horse at 6/4 in a 40p band and another in a 45p band.

The difference is small but it is real, and it is the reason the calculator on this site lets you type your bookmaker’s figure in directly. If you place a large bet at a long price, read the table in the terms of the bookmaker where you placed it. The deduction is applied by the bookmaker that took the bet, using its own rules.

More than one horse withdrawn

When two or more horses come out, the deductions are added together. Most published rules cap the total at 90p in the pound, so a winning bet always keeps something. A favourite at 7/4 and an outsider at 10/1 withdrawn together give 35p plus 5p, so 40p. Two short-priced horses at 1/4 and 2/5 would give 80p plus 70p, which is 150p on paper, and the cap holds it at 90p.

Some bookmakers’ rules set a higher cap than others. Coral’s shop rules, for example, mention 95p. The detail is in the terms, and a bet on a race with several withdrawals is the one where it is worth reading them.

Rule 4 on each way bets and multiples

An each way bet has a win part and a place part. The deduction reduces the winnings of both. The place part’s winnings are already a fraction of the win odds, so the deduction takes its share off that smaller figure. A horse that only places still pays a place return, a little smaller than it would have been.

A multiple, such as a double or an accumulator, can include a leg in a race where a horse was withdrawn. The deduction applies to that leg, and its effect carries through the rest of the bet because the leg’s price is part of the multiplied odds. How a bookmaker handles it is set out in its terms. The effect on a multiple is the same as the effect on a single: the winnings are smaller by the deduction on the affected leg.

Rule 4 and fixed prices against the starting price

Rule 4 applies to bets taken at a fixed price, such as an early price or a board price offered before the race. A bet at the starting price is settled at the SP, which is set after the withdrawal and already allows for the missing runner, so there is nothing for a deduction to correct. BetVictor’s racing rules describe the deduction as applying where you have taken a fixed odds price, and other bookmakers’ rules are to the same effect.

This is one reason bettors who prefer to avoid the uncertainty bet at the SP, and it is also why Best Odds Guaranteed exists: it lets you take an early price and still be paid at the SP if that is bigger. When the guarantee and a Rule 4 deduction apply to the same bet, the bookmaker’s terms say how they combine. BoyleSports, for one, states that it pays at the bigger odds after the Rule 4 deduction has been applied. Our Best Odds Guaranteed guide explains the guarantee, and the explainer shows how it pays.

What to do when a horse is withdrawn

Nothing needs doing. The bookmaker applies the deduction when it settles the bet, and you cannot opt out of it or ask for the original price. What you can do is check your open bets in the app or account, where a withdrawal is normally flagged, and see what the bookmaker’s own notice says about the deduction. If a bet carries an offer such as a boosted price or an extra place, read the terms of the offer too, since some promotions say what happens when a horse is withdrawn.

A withdrawal is not a reason to place another bet in a hurry. The market has moved, the prices on the remaining horses will have changed, and the new bet has to stand on its own.

Where to find a bookmaker’s Rule 4 terms

Look in the racing rules or the terms and conditions of the bookmaker, usually in the help centre under horse racing or non-runners. Most firms publish a table or link to one. The rule should say when a deduction applies, how it is worked out, how it is capped and whether it applies to each way and place bets. If a page is vague or has no date, treat it with caution and look for the version in force on the day of the race. Our horse racing betting sites guide lists ten UK-licensed bookmakers with their Best Odds Guaranteed terms, and each review says what we could and could not confirm.

Common misunderstandings about Rule 4

The first is that Rule 4 is a fee. It is not charged on top of your stake, and it does not apply to a lost bet. The second is that it applies to every withdrawal. It applies to a horse withdrawn after you placed a fixed-price bet and after the final declarations; a horse that was never declared does not trigger it. The third is that a bigger field means a bigger deduction. The price of the withdrawn horse decides the size, not the number of runners. The fourth is that Rule 4 is a bookmaker’s way of getting back money. It is a correction for a change in the market that applies the same way to every fixed-price bet on that race, and it is set by the published scales.

The last is the belief that a withdrawal can be avoided by choosing a different horse. A withdrawal is not something a bettor can predict, and a short-priced horse that is a doubtful runner is not a reason to bet at the starting price. Decide how much you are happy to stake, set a deposit limit in your account, and bet within it. Betting is for people aged 18 and over. If you want to talk to someone, GambleAware gives free, confidential help, and GamStop blocks every licensed UK site in one go.