You may also place your Win bet using Starting Price, or SP, rather than taking the odds on offer at the time. SP is the official starting odds for a horse, which is determined by a number of on-course bookmakers immediately after the start of the race.
Betfair's Starting Price ('SP' or 'Betfair SP') is calculated by balancing all SP bets and Exchange bets when the market is suspended at the 'off' of the relevant event. An SP bet cannot be cancelled once it has been placed.