Rule 4 Deductions at the Epsom Derby: What Happens When a Runner Is Withdrawn Late

You have picked your horse, placed your bet at a price you are happy with, and settled in to watch the Derby. Then, twenty minutes before the off, a runner is withdrawn. The bookmaker applies a Rule 4 deduction, and your potential payout shrinks. It happened to me in 2018 when a well-fancied contender was pulled out after the morning inspection, and the 15p-in-the-pound deduction cut my each-way return by more than I expected. The rules are clear once you know them, but the surprise catches plenty of punters off guard every year.

What Rule 4 Is and When It Applies to the Derby

Rule 4 – formally Tattersalls Rule 4(c) – exists to adjust the odds on remaining runners when a horse is withdrawn after the final overnight declarations but before the race is run. When a horse is taken out, the remaining runners have a better chance of winning, and the odds you took no longer reflect the true probability. Rule 4 corrects that by deducting a percentage from your winnings based on the price of the withdrawn horse.

The rule applies only to bets placed before the withdrawal is announced. If you place your bet after the withdrawal, your odds already reflect the reduced field and no deduction is necessary. This distinction matters on Derby morning: if you bet at seven o’clock and a horse is withdrawn at nine, Rule 4 applies to your bet. If you bet at ten o’clock and the withdrawal was announced at nine, it does not.

Rule 4 is a race-day mechanism. It does not apply to ante-post bets, which are settled on different terms. In the ante-post market, a withdrawn horse simply means your bet loses if you backed it, or the remaining market adjusts organically if you backed something else. The deduction framework is reserved for bets placed within the final 24 hours before the off.

The Deduction Scale: From 5p to 90p in the Pound

The size of the Rule 4 deduction depends on the price of the withdrawn horse at the time of withdrawal. The scale ranges from 5p in the pound for a longshot (14/1 or bigger) to 90p in the pound for an odds-on favourite. A withdrawn 4/1 shot triggers a 30p deduction. A withdrawn 6/1 shot triggers a 20p deduction. The shorter the price of the withdrawn horse, the bigger the impact on your payout.

For the Derby, where only three of the last ten favourites have won, the most disruptive scenario is the withdrawal of the market leader. If the favourite is trading at 3/1 and is pulled out, the deduction is 35p in the pound – meaning for every pound of profit you would have received, 35p is taken back. On a 50-pound bet at 8/1 that wins, your gross profit would be 400 pounds, but after the 35p deduction you receive 260 pounds. The gap between expectation and reality is significant.

Multiple withdrawals compound the deduction. If two horses are withdrawn, the deductions are added together, up to a maximum of 90p in the pound. Two mid-priced withdrawals in a Derby – unlikely but not impossible – could produce a combined deduction of 40p or more, materially altering the economics of every surviving bet in the market.

How Rule 4 Affects Each-Way and Forecast Bets

Rule 4 applies to both parts of an each-way bet. The deduction is taken from the win return and from the place return separately. If you have backed a horse each-way and it finishes in a place position but does not win, the deduction still reduces your place payout. On the Derby, where each-way is one of the most popular bet types, this can turn what looks like a solid place return into a disappointingly thin one.

The 2026 Derby’s prize fund of two million pounds guarantees a strong field, and strong fields tend to have multiple market movers in the ante-post phase. If one of those movers is withdrawn on the morning of the race, the Rule 4 deduction hits hardest on bets placed in the early-morning market, where the withdrawn horse’s price was still factored into the overall book.

Forecast and tricast bets are also subject to Rule 4 when a non-selected runner is withdrawn. The computer forecast and tricast dividends are recalculated to reflect the reduced field, and a deduction may be applied on top of that recalculation. In practice, the combined effect of the recalculation and the deduction means your exotic bet payout is reduced more than you might expect from the percentage alone.

Reducing Your Exposure to Rule 4 on Derby Day

The simplest way to avoid Rule 4 is to bet after all withdrawals have been announced. On Derby morning, there is usually a final declaration stage followed by a period during which trainers can withdraw horses. Waiting until the field is confirmed before placing your bet eliminates Rule 4 risk entirely – but it also means accepting the prices available at that later stage, which may be shorter if the market has moved.

Non-runner no bet offers provide an alternative route. Several bookmakers offer NRNB terms on selected ante-post markets, and some extend the offer to race-day bets on the Derby. Under NRNB, if your selected horse is withdrawn, your stake is returned rather than lost. This eliminates the risk of backing a non-runner but does not protect you from Rule 4 deductions triggered by other horses’ withdrawals.

My approach is a split strategy. I place the majority of my Derby stakes in the early morning to secure the best available prices, accepting the Rule 4 risk as a cost of doing business. I reserve a smaller portion of my stake for a top-up bet placed after the field is confirmed, at whatever price remains. This balances price optimisation against deduction risk – not a perfect solution, but a practical one. For a broader look at how timing your bets interacts with market movements and late intelligence, the race day guide covers the full pre-race timeline.