What is Rule 4 In Horse Racing | Rule 4 Deduction Guide

One of the most common questions that arises especially when betting on horse racing is, ‘Why is my bet not returning as per my expectations?’ The most common reason for this is the application of Rule 4, which comes into play when another horse backs off and, therefore, lowers the price of the horse you are backing. Here at OddsMonkey, we’ll look at what the rules are, why they are necessary, and how to use the tools available to you here at OddsMonkey if Rule 4 applies.

What is Rule 4 in Horse Racing

As previously mentioned, Rule 4 applies when a horse in a race withdraws and will not compete. This will definitely affect the race, because there is one less horse in the race, thus affecting the race’s chances. Introduced to compensate for a horse’s withdrawal, Rule 4 will reduce the chances of another horse later matching an upcoming race because the horse now running will have a better overall chance of winning.

For example, if a player backs a horse at odds of 6.0 and the favorite horse is priced at 2.0 if the favorite withdraws from the race, there will be a reduction in price as the probability of the horse winning increases. What the deduction is is the Rule 4 deduction. To learn more about this sport, check out our separate horse racing betting guide and our matched horse racing betting guide.

Why is the Rule of 4 Needed?

The Rule of 4 is necessary in horse racing to ensure the odds and profits remain fair, even if unfavorable circumstances occur, such as a horse withdrawing from a race. Horses of different prices will result in different deductions. If a horse with low odds withdraws, then the price of your horse will decrease by a greater amount compared to a horse with high odds.

Although this rule compensates drawn horses, there are exceptions to this rule. Reserves are most common in Irish horse racing but can be seen in certain races in the UK. Most bookmakers will not apply a Rule 4 deduction when a reserve withdraws, as they are not official runners. However, some bookmakers, such as Coral and Ladbrokes, use this rule in this situation, so make sure to be careful when placing your bets with certain bookmakers.

When might Rule 4 be triggered?

There are many reasons why Rule 4 may activate, and most of them are completely random and unpredictable. Here are some of the most common reasons that trigger Rule 4:

• Non-Runners – If a horse is withdrawn on race day, Rule 4 will most likely be declared, and this is the most common reason for Rule 4 to be used.

• Weather Conditions – Some horses are not suited to running in certain conditions, so some horses are withdrawn from the event in bad weather, such as heavy rain. This is usually done to protect the horse.
• Veterinary Intervention – It is possible that a veterinarian will recommend that a horse be withdrawn from the race once the betting markets open.
• Jockey Problems – Rule 4 can be applied if a horse is declared a non-runner because a jockey was injured in a previous race.

Rule 4 Example

Let’s look at a real-life example of how Rule 4 deductions can affect your horse racing betting. For example, you place a £10 bet on a horse at odds of 4/1, and just before the race starts, another horse is drawn at odds of 7/1. Let’s look at a step-by-step guide on how Rule 4 reductions will affect betting:

• Potential Win: £40
• Rule 4 Deduction for 7/1 non-runners: 10 pence per pound
• Amount Deducted: £40 x 0.10 = £4
• Adjusted Return: £40 – £4 = £36
• Total Return = £36 + £10 bet = £46

Rule 4 Calculator

In typical OddsMonkey fashion, we have a calculator available for players to use if Rule 4 applies. Use our Rule 4 calculator to help calculate your horse’s odds after the Rule 4 subtraction. There is a formula for players to calculate the subtraction themselves, but it is recommended to use a calculator as the mathematical formula used is complicated.

(Decimal Odds – 1)

This is the formula used for the Rule 4 calculator; however, the calculator makes it simpler as the player only needs to enter the odds back and put, then the Rule 4 subtraction and subtraction factor to then create the new odds the player needs.

If we use the example of the previous horse with back odds of 6.0, then the new odds are 3.75 with this formula. There are two other important factors to consider:

1. If the horse is priced at odds of 15.0 or more, then the price of your horse will not be reduced
2. Rule 4 only applies to the bookmaker’s odds; there are different ways to calculate exchange price changes.

Rule 4 On the Exchange

Betting exchanges work in a different way to bookmakers when rule 4 is applied, as each horse is assigned a ‘Reduction Factor’ based on the estimated price and displayed as a percentage. Once a horse is withdrawn, the reduction percentage will apply to all other horses in the race.

If you place a bet on a horse, the horse’s loss amount is usually about the same, with minimal differences, meaning over time it will most likely be the same.

How to Prepare Yourself For a Rule 4 Deduction

Rule 4 deductions can occur after a bet has been placed, which means it can be very difficult to avoid them, as they can occur in any race at any time. It is important that you plan these deductions keeping the following tips in mind.

✅Watch for odds shifts – If there is a large change in odds, this could indicate that one of the runners will be drawn.

✅Consider the reduction before placing a bet – Before placing a bet, consider the possibility of a reduction, make sure you know all the possibilities of the bet.

✅Pay attention to announcements – When you place a bet, be sure to pay attention to any announcements made on the race, as these will let you know if a horse has withdrawn.

Learn More About Matched Betting At OddsMonkey

Rule 4 can slightly change how matched betting works and affect the amount of profit generated. Because the odds change in a race, it is important to ensure that the price and odds on a tour horse remain the same even after Rule 4 is applied. If this is not the case, your back and lay bets are not matched correctly and could potentially result in losses rather than locked in profits. This is just one of many components that can influence matched betting; we have a dedicated matched betting blog that can be useful for players interested in learning more!

Rule 4 FAQ

Because Rule 4 deductions can be confusing, there are some frequently asked questions surrounding the topic, which we’ll cover here.

What happens if several horses are withdrawn from a race?

There can be more than one Rule 4 deduction; however, the total Rule 4 reduction may not exceed 90%.

Does the Rule 4 reduction affect betting stakes?

No, the Rule 4 deduction only impacts profits from successful bets. If your horse wins, you will get your initial bet back along with the proceeds.

Do all bookmakers use Rule 4?

All bookmakers use Rule 4 deductions as this is the industry standard rule.