General
The Rule 4 deduction is an industry standard where a quoted deduction is applied for every 1.00 unit of currency won.
When Sportsbooks offer odds on an event, they do so expecting all participants to take part. When a participant is withdrawn from a multi-participant market (not 2-way) a Rule 4 deduction is applied to all bets placed before the withdrawal, to reflect the reduced amount of competitors.
The size of the deduction is dependent on the odds of the withdrawn participant(s) at its time of withdrawal, the shorter the odds the larger the Rule 4 deduction.
Rule 4 (Deductions) Table
Deduction Table for scratches other than Futures – Cents in the $.
Should a participant withdraw and a new market formed then any bets laid at prices prior to the new market will be subject to the above deductions. In the event of a further withdrawal after the market has been reformed then bets placed at prices in the original market will be subject to a further deduction based on the price of the withdrawn participant in the original market. Bets placed in the new market will be subject to a deduction based on the current price of the withdrawn participant.