Learn what Rule 4 deductions are and how they affect winnings on horse racing bets.
Rule 4 is a reduction applied to winnings when a horse is withdrawn (non-runner) from a race after prices are set. With fewer runners, the remaining horses should be shorter prices, so bookmakers reduce the WINNINGS part of affected bets by a set amount. Your stake is not reduced.
• Day-of-race bets placed before the non-runner is announced are usually affected.
• Multiple non-runners can lead to multiple deductions (bookmakers cap the total at their stated maximum).
• Exchanges apply their own ‘reduction factors’ to matched bets; these aim to mirror the change in the market price.
If your back and lay bets were both fully matched before the non-runner, the bookmaker deduction and the exchange reduction factor usually move the two sides in the same direction. The final result is often within a few pence of your original plan. Two things to watch:
• Minimum-odds offers: if the bookmaker’s effective odds fall below the promo’s minimum after a deduction, it may no longer qualify.
• Places & terms: non-runners can change the number of places paid in each-way markets. Re-check place terms near the off.
• Prefer day-of-race markets rather than ante-post if you want to minimise surprises.
• Check for recent non-runners or going changes that might cause more withdrawals.
• Re-check the bookmaker’s terms and the exchange market close to the off; recalc your plan if the field changes.
