Rule 4 Deductions (Non-Runner Rule) Explained: A Complete Guide

Rule 4 deductions in horse racing are commonplace, while they also sometimes apply in greyhound racing. What is a Rule 4 you might ask? It's basically part of the Tattersalls Rules of Racing and is used to reflect the market change when a horse is withdrawn at the start or becomes a non-runner after the market has formed.

What is a Rule 4 Deduction in Betting?

The rules of racing are used to govern betting with bookmakers. Rule 4 (officially Tattersalls Rule 4(c)) determines that a standard deduction is made from winning bets when a horse is withdrawn from a race after the final declaration stage.

Its purpose is to create a fair market for the bookmakers and other punters after a non-runner has been declared, ensuring that betting odds are reflective of the non-runner.

Why Does Rule 4 Exist?

When a horse is withdrawn, the remaining horses have a better chance of winning. Punters who have already placed bets on other horses have effectively got better odds than they would have if the non-runner had not been in the race. Horse racing Rule 4 acts as a mechanism for adjusting these starting prices (SP) and payouts to reflect the new state of the market once a non-runner has occurred.

How Rule 4 Deductions are calculated

The size of the betting deductions depend on the odds of the withdrawn horse at the time of its withdrawal. The shorter the price of the non-runner, the larger the deduction, as this is reflective of the chance the non-runner had of actually winning the race.

The table below shows the amount in pence that is deducted from every £1 of winnings, while you will easily find a Rule 4 calculator online.

Rule 4 Calculation Examples

Below is an example of how the non-runner rule is applied to a bet struck before a horse is taken out of the market.

Example 1: (Simple): You bet £10 on a horse at 10/1. A different horse is withdrawn, priced at 7/2. Your horse wins. The Rule 4 deduction for a 7/2 non-runner is 20p in the £. Your winnings are £100. The deduction is £100 x 0.20 = £20. Your revised winnings are £80, and your total return is £90.

More than one Rule 4 deduction can apply if more than one horse withdraws from a race, but the total deductions won't exceed 90p in the £.

When Does Rule 4 Not Apply?

There are some instances where the non-runner rule doesn't apply, these include:

• If the bet is placed after the non-runner is declared and the market has been reformed.
•  If the bet is placed on an “ante-post” market.
• If the bet is placed with a “Non-Runner No Bet” concession.
• If the bet is settled at Starting Price (SP), as the SP is calculated on the final field of runners.

Rule 4 and Best Odds Guaranteed (BOG)

In the instance where a punter has taken a BOG promotion, Rule 4 is applied differently. The deduction is applied first to the original price taken, and then the comparison with the SP is made to see which price is better for the punter.

The best odds guaranteed is still applicable, bookmakers usually apply BOG first, then apply Rule 4 to the adjusted odds.