Understanding Horse Racing's Rule 4: Impact & Insights

Understanding Horse Racing's Rule 4: Impact & Insights

What is a Rule 4 in Horse Racing?

In Horse Racing, a Rule 4 is applied to all winning bets on a race before a non-runner. This is when a horse is withdrawn between the events of the final declarations for a race (usually 48 hours before the start time) being made and the off time of the race. A Rule 4 results in a deduction of returns to a winning bet - the amount of the deduction depends on the horse's price at the time it was withdrawn.

Why are Rule 4s implemented?

Rule 4s are implemented to protect bookmakers when there are non-runners. To put that into an example, let us say that a horse, who was favourite with odds of 2/1, is withdrawn from a race half an hour before the start time. Consequently, the odds of the remainder of the runners will change as they now have a greater chance of winning as the favourite is no longer running. 

The bookmakers have to issue a refund for all the bets on the favourite, but they will have already taken bets on the rest of the horses at the (bigger) odds prior to the 2/1 favourite being withdrawn. To bring the returns of those bets down in line with the prices following the withdrawal of the favourite, a Rule 4 is applied. This levels the playing field and makes it fair across the board for bookmakers and punters.

When will my bet not be affected by a Rule 4?

There are a few occasions where your bet won’t be affected by a Rule 4. The first of those is when you bet ante-post, which is when you place a bet on a horse before the final declarations.The lowest Rule 4 deduction is 5c for every €1. Some bookmakers have waived that particular Rule 4, so check with them to see what deductions apply.

If you place your bet after a horse has been declared a non-runner, then you won’t be subject to a Rule 4 if your bet is a winner. Lastly, if you select SP (starting price) when placing your bet, you won’t be affected by a Rule 4 regardless of when you have placed your bet. These reasons are because the bookmakers adjust their prices after a horse is withdrawn, so the removal of the non-runner in the betting has been taken into account for your bet.

What happens if more than one horse is withdrawn?

Sometimes, there may be more than one horse taken out of a race after the final declarations have been made. In this instance, multiple Rule 4s could be applied. If there are two non-runners and you have placed your bet before both of the horses have been withdrawn, then two Rule 4s will apply to your bet. 

So if the first withdrawn horse results in a 10c deduction and the second a 15c deduction, those will be combined for a 25c Rule 4. But if you place a bet after the first non-runner but before the second, your bet would only be subject to the 15c Rule 4 as the price changes following the first withdrawal will have already been taken into account.

How much will be deducted from my winnings if there is a Rule 4?

The Rule 4 deduction refers to the amount your winnings will be reduced by for every €1. For example, a 10c Rule 4 means that for every €1 you win, 10c will be deducted.

   Odds    Decimals    R4 Deduction
    1/9 or shorter1.11 or shorter    90c

2/11 to 2/17

 1.18 to 1.12    85c
    1/4 to 1/5 1.25 to 1.20    80c

3/10 to 2/7

    1.30 to 1.29    75c
    2/5 to 1/3    1.40 to 1.33    70c
    8/15 to 4/9

 1.53 to 1.45  65c
    8/13 to 4/7    1.62 to 1.5760c
    4/5 to 4/6    1.80 to 1.6655c
    20/21 to 5/61.95 to 1.8350c
 Evens to 6/5    2.00 to 2.20 45c


Rule 4 is a standard deduction applied when a horse is withdrawn from a race after betting has commenced, affecting the odds of other runners. The deduction is based on the odds of the withdrawn horse and aims to maintain fairness in betting markets.

When a horse is withdrawn, Rule 4 deductions reduce potential payouts for winning bets on remaining horses. The size of the deduction depends on the odds of the withdrawn horse, impacting the final odds and subsequent winnings.

While specific Rule 4 deductions aren't known until a horse is withdrawn, anticipating potential non-runners and monitoring odds changes can help bettors gauge possible impacts on their bets.