Your horse won, and the returns came back lighter than the slip suggested. Rule 4 is usually the reason. It is a standard, published adjustment rather than anything arbitrary, and it is straightforward to check for yourself.
Why the deduction exists at all
When a horse is withdrawn after betting has opened and there is no time to form a new market, everyone still in the race has a better chance of winning than the price you took reflected. You are, in effect, holding a bet struck at odds that no longer match the race being run.
Rule 4 corrects for that. Bookmakers reduce payouts on affected bets by a published amount, based on how likely the withdrawn horse was to win. It is a standard industry adjustment under Tattersalls Rule 4(c), not a discretionary decision by your bookmaker.
- It applies only to bets struck before the withdrawal.
- Bets taken after the market re-formed are unaffected.
- Ante-post bets are generally exempt.
How the amount is worked out
The deduction is set by the withdrawn horse's price at the moment it was withdrawn, on a fixed scale expressed in pence per pound of winnings. A short-priced withdrawal removes a serious contender, so it takes more: 1/9 or shorter costs 90p in the pound. Anything longer than 14/1 is treated as having had little effect and costs nothing at all.
If more than one horse comes out, the deductions are added together, capped at 90p in total. Two withdrawals at evens and 3/1 mean 45p plus 25p, so 70p — a substantial reduction, and worth checking rather than accepting on trust.
- Shorter withdrawn price means a larger deduction.
- Longer than 14/1 means no deduction.
- Multiple withdrawals stack, up to a 90p ceiling.
The mistake almost everyone makes checking it
Rule 4 comes out of winnings only. Your stake is returned in full. Applying the deduction to your total returns instead overstates it every time, and is the usual reason a hand-checked figure disagrees with the bookmaker's.
Take a £10 bet at 5.0 with a 25p deduction. Winnings of £40 are reduced by a quarter to £30, so you receive £40 back — the £30 plus your £10 stake. Deducting from the £50 total would suggest £37.50, which is wrong by £2.50 and would have you querying a correct settlement.
- Deduct from profit, then add the stake back.
- Never apply the percentage to total returns.
- Each-way bets take the deduction on whichever parts won.
Why it matters beyond the individual bet
A deduction quietly changes the price you actually struck, which matters if you track closing line value. A bet taken at 5.0 with a 25p Rule 4 was effectively struck at 4.0 — so against a 4.0 closing price it produced no value at all, rather than the +25% an unadjusted comparison would suggest.
Records that ignore Rule 4 therefore overstate both returns and price quality. Over a season of racing bets that drift is easily large enough to change what your data appears to be telling you about your own judgement.
- Record the deduction, not just the headline price.
- Unadjusted CLV flatters any record containing withdrawals.
- Check settlements rather than assuming they are right.
FAQ
Common questions
How do I check a Rule 4 deduction myself?
Deduct from winnings only, then add the stake back. A £10 bet at 5.0 with a 25p deduction returns £40: winnings of £40 cut by a quarter to £30, plus the £10 stake. Applying 25p to the £50 total gives £37.50, which is wrong by £2.50 and is the usual reason a hand-checked figure disagrees with the bookmaker.
What happens if two horses are withdrawn from the same race?
The deductions are added together and capped at 90p in total. Withdrawals at evens and 3/1 mean 45p plus 25p, so 70p in the pound comes off your winnings.
When does Rule 4 not apply?
It applies only to bets struck before the withdrawal. Bets taken after the market re-formed are unaffected, ante-post bets are generally exempt, and a horse withdrawn at longer than 14/1 carries no deduction at all.
Does a Rule 4 deduction affect closing line value?
Yes, and records that ignore it overstate price quality. A bet taken at 5.0 with a 25p deduction was effectively struck at 4.0, so against a 4.0 closing price it produced no value — not the +25% an unadjusted comparison would suggest.
Free tools
- Rule 4 calculator
Work out the deduction from the withdrawn horse's price and check your returns.
- CLV calculator
See what a Rule 4 deduction does to the value of the price you took.
Related
- CLV tracker
How Rule 4 sits in a closing line value comparison on a UK racing record.
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