How Rule 4 works
When you take a price, it's based on the whole field. If a horse is then withdrawn, especially a fancied one, every remaining runner has a better chance of winning, and your price is now bigger than it should be. Rule 4 corrects that with a deduction from your winnings, set by the price of the horse that was withdrawn. Your stake is never touched.
The deduction is expressed in pence per pound. A 25p deduction means 25p comes off every £1 of winnings, so you keep 75% of them.
The Rule 4 deduction table
This is the standard scale from the Tattersalls Rules on Betting (Rule 4(c)), which UK bookmakers use:
| Price of the withdrawn horse | Deduction per £1 of winnings |
|---|---|
| 1/9 or shorter | 90p |
| 2/11 to 2/17 | 85p |
| 1/4 to 1/5 | 80p |
| 3/10 to 2/7 | 75p |
| 2/5 to 1/3 | 70p |
| 8/15 to 4/9 | 65p |
| 8/13 to 4/7 | 60p |
| 4/5 to 4/6 | 55p |
| 20/21 to 5/6 | 50p |
| Evens to 6/5 | 45p |
| 5/4 to 6/4 | 40p |
| 13/8 to 7/4 | 35p |
| 15/8 to 9/4 | 30p |
| 5/2 to 3/1 | 25p |
| 10/3 to 4/1 | 20p |
| 9/2 to 11/2 | 15p |
| 6/1 to 9/1 | 10p |
| 10/1 to 14/1 | 5p |
| Over 14/1 | No deduction |
Worked example
You back a horse at 5/1 with £10 and it wins, but a rival priced at 3/1 was withdrawn. That's a 25p deduction. Your winnings would have been £50. A quarter of that comes off, so you collect £47.50 instead of £60.00.
More than one non-runner
If several horses are withdrawn from the same race, their deductions are added together, but the total can never exceed 90p in the pound. Even at the maximum, the same £10 bet at 5/1 would still return £15.00: your stake plus 10% of the winnings. Add each non-runner in the calculator and it applies the cap automatically.
Rule 4 and the place part of each way bets
The deduction applies to the place part as well, after the place fraction has been worked out. Turn on each way in the calculator and choose whether your horse won or placed.
Common questions
Does Rule 4 apply to starting price bets?
Usually not. When a horse is withdrawn, the betting market re-forms and the starting price reflects the smaller field, so SP bets are settled at the SP with no deduction. The exception is a withdrawal so late that there's no time for a new market, in which case the deduction can apply to SP bets too.
Does Rule 4 apply to each way bets?
Yes. The same deduction comes off the winnings on both the win part and the place part.
How can I avoid Rule 4?
Bet at SP, or look for "non-runner no bet" offers, which some bookmakers run on big races. These refund your stake if your own horse doesn't run, but they don't stop Rule 4 deductions when other horses are withdrawn.
Does Rule 4 apply in greyhound racing?
Yes, the same principle applies when a dog is withdrawn after prices are formed, although it comes up far less often than in horse racing.