Rule 4 is a mechanism through which deductions are made to horse racing bets when a runner withdraws from a race. This rule is often not known or misunderstood by casual punters. Subsequently, it can cause a certain amount of shock when deductions are made to someone’s returns without any further explanation.
Why Rule 4 Deductions Exist
Rule 4 deductions are made to account for the change in dynamics of a race. When a horse withdraws after the line-up has announced, it affects the remaining runners’ chances of winnings. For example, if there were six runners in a race and one pulled out, the remaining horses would only have to beat four competitors rather than five. Because of the physical changes to the race, the odds of those remaining need to adjust accordingly.
For those that place a bet after a withdrawal, the advertised odds will reflect the new dynamics. However, if you’ve already made a bet and locked in the odds, the changes won’t be reflected in the price you received. Therefore, bookmakers have to make deductions after the race is over and before the payout is processed. These are Rule 4 deductions.
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Rule 4 Deductions Calculator
Now that you can answer the question “what’s rule 4 in horse racing”, the next thing to think about is how the deductions are made. We know that a change of dynamics can initiate Rule 4, but how do bookmakers calculate the amount to deduct from a bet?
Rule 4 deductions are calculated by looking at the odds of the horse that’s been withdrawn. It’s important to note that the deductions apply only to the win portion of your bet. In other words, only money from your profit is deducted, not from your stake.
In general, Rule 4 deductions are expressed as percentages. However, you can put these into financial terms by thinking about the rate of €1. For example, a 20% reduction means you’ll lose €0.20 for every €1 you bet. From here, a Rule 4 calculator is used to generate a percentage based on the odds of the horse that’s been withdrawn (see table below).
Rule 4 Deductions Table
|Odds of Horse Withdrawn||Percentage/Cash Deduction|
|1/9 (1.11) or shorter||90% deduction (i.e. €0.90 for every €1 wagered)|
|2/11 (1.18) to 2/17 (1.12)||85% (i.e. €0.85 for every €1 wagered)|
|1/4 (1.25) to 1/5 (1.20)||80% (i.e. €0.80 for every €1 wagered)|
|3/10 (1.60) to 2/7 (1.29)||75% (i.e. €0.75 for every €1 wagered)|
|2/5 (1.40) to 1/3 (1.33)||70% (i.e. €0.70 for every €1 wagered)|
|8/15 (1.53) to 4/9 (1.44)||65% (i.e. €0.65 for every €1 wagered)|
|8/13 (1.62) to 4/7 (1.57)||60% (i.e. €0.60 for every €1 wagered)|
|4/5 (1.80) to 4/6 (1.67)||55% (i.e. €0.55 for every €1 wagered)|
|20/21 (1.95) to 5/6 (1.83)||50% (i.e. €0.50 for every €1 wagered)|
|Evens (2.00) to 6/5 (2.20)||45% (i.e. €0.45 for every €1 wagered)|
|5/4 (2.25) to 6/4 (2.50)||40% (i.e. €0.40 for every €1 wagered)|
|13/8 (2.63) to 7/4 (2.75)||35% (i.e. €0.35 for every €1 wagered)|
|15/8 (2.88) to 9/4 (3.25)||30% (i.e. €0.30 for every €1 wagered)|
|5/2 (3.50) to 3/1 (4.00)||25% (i.e. €0.25 for every €1 wagered)|
|10/3 (4.33) to 4/1 (5.00)||20% (i.e. €0.20 for every €1 wagered)|
|9/2 (5.50) to 11/2 (6.50)||15% (i.e. €0.15 for every €1 wagered)|
|6/1 (7.00) to 9/1 (10.00)||10% (i.e. €0.10 for every €1 wagered)|
|10/1 (11.00) to 14/1 (15.00)||5% (i.e. €0.05 for every €1 wagered)|
|Over 14/1 (over 15.00)||No Deduction|
Rule 4 for Betting Exchanges
In exchange betting, horse racing Rule 4 deductions still apply but in a slightly different way. At platforms such as Betfair, a “reduction factor” is used to calculate how much to deduct from your profit. This factor is based on a horse’s chances of winning the race.
For example, if a reduction factor of 25% was set, then the traded price on all previously matched bets would be reduced by 25%. So, if you placed a €10 bet on a horse with a traded price of 8.0, your potential profit would be €70. However, if a 25% reduction factor is in action, you’d receive 75% of €70, which is €52.50. This means the revised traded price of your pick would be 6.25.
How the Best Online Bookmakers apply Rule 4
When a bookmaker sets a price, they do it on the basis that all planned runners will take part. Therefore, when a horse is withdrawn, it’s only fair that the odds change to reflect that. Let’s take a look at some of the best in the business and how they do it.
Bet365 Rule 4
Bet365 Rule 4 deductions are some of the best in the business. In order to give you more, there are no 5p deductions, meaning that the first horse withdrawn with odds of between 10/1 and 14/1 won’t affect your returns. As you’d expect, Rule 4 deductions apply to win and place bets.
William Hill Rule 4
Rule 4 William Hill standards are better than most. Like its peers, the first 5p deduction doesn't count. In other words, if the total Rule 4 deduction is €0.05, William Hill won’t take any money from your winnings. Additionally, total Rule 4 reductions won’t exceed €0.90, regardless of how many horses are withdrawn.
Unibet Rule 4
Unibet Rule 4 deductions are fairly standard. However, this operator also has something known as Tattersalls Rule 4. Under these rules, deductions on win bets are capped at 75% (non-runners odds were 1.30). Deductions on place bets are capped at 55% (non-runners odds were 1.06 or shorter).
Coral Rule 4
Coral Rule 4 deductions follow industry standards both in terms of reductions and what happens when multiple horses are withdrawn. Basically, the deductions can range from nothing to 90%. Additionally, if multiple horses are withdrawn, the price can be adjusted multiple times.
Rule 4 is so-called because it’s listed as Rule 4(C) in the Tattersalls Committee rules on betting. The reason it’s in place is to ensure that the payout odds reflect a change in race dynamics. Therefore, because a horse has been withdrawn, you’ll receive a lower than expected payout due to Rule 4.
Other than the Rule 4 exceptions mentioned in our bookmaker reviews, the main thing you need to know is when a horse was withdrawn. If the race hasn’t been declared (i.e. the line-up finalised), then the bet is declared as an ante-post bet. In these situations, bets on non-runners are classed as losers, rather than being subject to Rule 4.
If multiple horses are withdrawn, multiple deductions will be made. In simple terms, the price is recalculated after a single withdrawal. Subsequent Rule 4 deductions are made on the recalculated price.
If the number of runners becomes equal to or less than the number of paid places in a race, reverse Rule 4 applies. This means your odds lengthen because you’ll have more chance of winning the bet than you previously had.
Yes. Rule 4 is an industry-wide standard that all bookmakers use for horse racing events. Even though you might not like seeing your returns reduced, it’s the only fair way to ensure everyone, including the bookmakers, are happy.
Other than reading this guide and understanding the nuances of Rule 4 horse racing standards, you’ll only know if a deduction has been made when you receive your pay-out. If in doubt, as the bookmaker your placed the bet with.