Rule 4 Deductions Explained
Why winnings are cut when a horse is withdrawn, how the published scale works and what it costs you.
When a horse is withdrawn after a market has been priced and there is no time to form a new one, the bookmaker applies a Rule 4 deduction. It comes off your winnings only, never your stake, and the size of the cut depends entirely on the price of the horse that came out. That last point is where most punters get caught. A Rule 4 is not a flat haircut. A withdrawn favourite and a withdrawn 20/1 outsider do completely different things to your return, and one of them does nothing at all.
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Why Rule 4 exists
The logic is arithmetic, not punishment. You backed a horse in a field of a certain size against a certain set of rivals. Take one of those rivals out, especially a short-priced one, and every horse left in the race has become more likely to win. The odds you accepted no longer reflect the race you are actually betting into.
A horse priced at 5/2 is withdrawn before the off, so the published scale calls for a deduction of 25p in the pound of winnings.
| Line | Amount |
|---|---|
| Stake | £10 |
| Winnings before the deduction | £100 |
| Deduction at 25p in the pound | −£25 |
| Winnings paid | £75 |
| Total return | £85 |
The deduction never touches the stake. On the published scale a withdrawal at around even money costs 45p in the pound, one priced between 6/1 and 9/1 costs 10p, and a horse longer than 14/1 triggers no deduction at all.
A bookmaker's options at that point are limited. If the withdrawal happens minutes before the off, there is no realistic window to void every bet, reprice the book and take the business again. So the price stands and the deduction does the correcting, applied in pence in the pound against the winnings, as explained in secondary sources. Worth being precise about the mechanics, because this is the single most common misunderstanding in the whole area: your stake is never touched. Only the profit is reduced.
How to read the scale
The deduction follows a published scale keyed to the odds of the withdrawn horse at the moment it comes out — not its morning price, not its opening show. A horse that was 4/1 overnight and 6/4 when the vet pulls it is treated as a 6/4 withdrawal.
At the short end, a withdrawal at around evens costs 45p in the pound. Mid-range, a withdrawal priced between 6/1 and 9/1 costs 10p in the pound. And anything longer than 14/1 triggers no deduction whatsoever, on the grounds that a rank outsider leaving the race barely moves the true chance of the survivors.
What happens to bets placed after the withdrawal
Bets struck once the market has been reformed, at the new prices, are not subject to the deduction. You are already betting into the corrected race, so there is nothing left to correct. This is the reason a Rule 4 can look arbitrary to two punters standing next to each other with the same selection: the one who backed it ten minutes earlier carries the deduction, the one who backed it ninety seconds later does not.
Greyhound racing works the same way
The same guide states that where the withdrawn dog's price was 1/9 or shorter, the deduction reaches 90p in the pound. That is close to the entire profit gone, which tells you how heavily an odds-on withdrawal distorts a six-dog race. Do not assume the table transfers cleanly to every other sport or market type. The rule as described here covers horse and greyhound racing.
The worked example, line by line
Now a horse priced at 5/2 is withdrawn before the off. The published scale calls for a deduction of 25p in the pound.