Rule 4 Explained: Deductions Table & Worked Examples

Rule 4 is the deduction that surprises punters who have never heard of it: you back a winner, then the returns come up short. It is not the bookmaker shaving your money for fun. When a horse is withdrawn after the market has formed, the remaining runners’ chances improve, so the bookmaker reduces winnings to rebalance the book. This guide explains why Rule 4 happens, gives the full deduction table by price, works through examples, and covers the tricky cases like multiple withdrawals.

What Rule 4 is and why it happens

When you take a price, that price reflects the horse’s chance against the whole field. If a fancied rival is then withdrawn, say it refuses to enter the stalls or is pulled out late, the race becomes easier for everyone left in. Your horse’s true chance has improved, so the price you took is now too generous. Rule 4 (named after the Tattersalls Committee rule that governs it) corrects this by deducting an amount from your winnings in proportion to how strong the withdrawn horse was.

The key trigger: the deduction applies to bets struck at a fixed price before the withdrawal. The shorter the withdrawn horse’s price, the more it was expected to affect the race, so the bigger the deduction. It is the bookmaker keeping the book fair, not penalising you, and it applies to everyone who took an early price on any runner in the race.

The Rule 4 deduction table

Deductions are taken in pence per pound of winnings, based on the odds of the withdrawn horse at the time it was pulled out. This is the standard scale:

The deduction comes off your winnings only, not your stake. Our Rule 4 calculator works out the exact figure for any bet in seconds.

A worked example

You back a horse at 6.0 (5/1) with a £10 stake, so your winnings would be £50. Before the off, the 2/1 favourite is withdrawn. From the table, a withdrawn horse at 2/1 (between 15/8 and 9/4) carries a 30p deduction.

• Winnings before deduction: £50.
• Deduction: 30p in the pound, so 30% of £50 = £15.
• Winnings after Rule 4: £35, plus your £10 stake back, for £45 returned.

Your £10 stake is always safe; only the profit is reduced.

Rule 4 on an each-way bet

Rule 4 applies to both parts of an each-way bet. Say you have £10 each-way (£20 total) on a horse at 10/1 that places, returning a place part calculated at, for example, 5/4. If a 5/1 chance is withdrawn before the off, the 10p-in-the-pound deduction is taken from your winnings on both the win part (if it wins) and the place part. The stake is never touched; the deduction only ever reduces the profit. The Rule 4 calculator handles the each-way maths so you can see the net return.

Multiple withdrawals

If more than one horse is withdrawn, the deductions are added together. Two non-runners at, say, 4/1 (20p) and 5/1 (10p) combine to a 30p-in-the-pound deduction. Crucially, the total deduction is capped at 90p in the pound however many horses are withdrawn, so your winnings can never be wiped out entirely by Rule 4. Multiple late withdrawals are most common in big, competitive fields, and the combined deduction can be significant, which is worth knowing before you judge a settled bet.

When Rule 4 does not apply

• Withdrawn horse bigger than 14/1. A longshot dropping out barely changes the race, so no deduction is taken.
• Bets struck at SP after the withdrawal. If you bet at starting price after the market reformed, the new prices already reflect the smaller field.
• Reformed markets. If a bookmaker forms a fresh market after a withdrawal, bets on the new market are not subject to that deduction.
• Withdrawal before your bet. If the horse came out before you placed your bet, the price you took already accounts for the smaller field.

Rule 4 is also relevant to ante-post betting, where late withdrawals of other runners can reduce winnings on bets placed weeks earlier.

Rule 4 on the exchanges

Betting exchanges handle this slightly differently. On a fixed-odds bet you placed at an exchange’s starting price, a Rule 4-style reduction factor is applied in the same spirit. On standard back bets matched before a withdrawal, exchanges apply their own reduction factor based on the withdrawn horse’s price, published at the time. The principle is identical: the book is rebalanced so the remaining runners’ improved chances are reflected. Always check the specific platform’s rules, as the exact mechanism can vary.

Rule 4 is routine, not a rip-off: it keeps the odds fair when the field changes. Knowing the table, and that multiple withdrawals stack up to a 90p cap, means the settled returns never surprise you. Our bookmaker reviews cover how clearly each firm shows deductions. Keep stakes sensible, and if betting stops being fun, our responsible gambling tools can help.

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