How is betfair sp arrived at?

Most informative...

is it just an arrive of the very lasy lay and back price just before off? or is it an average in say last minute?

celtic son: i thought some friendly person might know and be willing to tell me!

10. RULES FOR BETFAIR STARTING PRICE

· Betfair's Starting Price ('SP' or 'Betfair SP') is calculated by Betfair Limited (i.e. the UK exchange) or in the case of Australian events by Betfair Pty Limited, by balancing all SP bets and exchange bets when the market is suspended at the 'off' of the relevant event. The details of this calculation are provided directly below. Please note that for all Betfair customers, an SP bet cannot be cancelled once it has been placed.

· A bet at Betfair SP is a fixed odds bet, with the odds on each selection being calculated and bets matched when the event starts. The odds are calculated by matching SP backers and exchange backers against SP layers and exchange layers. The inclusion of exchange bets in the SP reconciliation is necessary to ensure that: SP backers get the benefit of unmatched exchange offers to lay if those offers could increase the SP; and SP layers get the benefit of unmatched exchange offers to back if those offers could reduce the SP. Including unmatched exchange offers in the SP reconciliation also ensures that the bets of exchange backers and layers, which would otherwise lapse, are matched where possible.

· The minimum liability for a bet placed at Betfair SP is £10 for a lay bet and £2 for a back bet (or the currency equivalent in each case).

· Example 1: on selection A there is £1,000 of backers' stakes and £6,000 of layers' liabilities at Betfair SP and there are £500 of unmatched exchange back bets available to lay at an average of 5.0. If we ignored the exchange market in this case the SP would be 7.0. However this would leave exchange back bets, that could also have been matched at their requested price against SP layers, unmatched. Therefore the Betfair SP will be 5.0 and all SP backers and SP layers will be matched at that price. The £500 of exchange backers' stakes will also be matched at their requested price of 5.0 against the SP layers.

· Example 2: on selection B there are £831 of backers' stakes and £4,428 of layers' liabilities at Betfair SP and the following unmatched exchange lay bets, available to back: £20 at 6.8, £31.13 at 6.6 and £100 at 6.4. In this case the Betfair SP will be 6.68. This is calculated by including the £20 available to back at 6.8 and the £31.13 available to back at 6.6 and balancing those amounts against the SP backers' stakes and SP layers' liabilities. The £100 available to back on the exchange at 6.4 remains unmatched as to include any of this amount would lead to an imbalance between SP backers and SP layers.

· For more details on how Betfair undertakes the SP reconciliation process, please see the FAQ section of the Betfair SP microsite.

· If for whatever reason the site is unavailable when an event starts or the SP cannot otherwise be reconciled at the 'off', Betfair will determine the SP using all available information. For the avoidance of doubt this information will not be limited to betting activity on the relevant Betfair market(s). Also in these circumstances, a licensed betting operator within the Betfair group may act as counterparty to SP bets if necessary to ensure a fair SP. The Betfair personnel involved in determining the SP in such circumstances will have no undeclared personal or other interest in the SP in question.

· If the SP reconciliation process is undertaken prematurely (for example if a horserace is turned in-play in error), then Betfair will endeavour to reverse the reconciliation so that the SP is determined when the event actually starts. There may however be circumstances in which this is not possible, in which case the SP will be based on the initial reconciliation.

· In cases where an SP reconciliation is reversed: SP bets (including SP limit bets), 'At In-play: Take SP' bets and 'At In-play: Keep' bets will all revert to their status before the reconciliation; and 'At In-play: Cancel' bets will either remain cancelled if not matched as part of the reconciliation process, or if matched as part of the reconciliation process, will revert to their unmatched status before the reconciliation.

· If the SP reconciliation process is undertaken later than scheduled (i.e. after the event has started) and Betfair determines that a material event has occurred (this will generally mean that the event is not turned in-play), the SP will be determined based solely on SP bets (and