An Exchange bet is a normal bet placed by choosing the odds of your selection from the market view (as opposed to clicking on the ‘SP’ of your selection). When an Exchange bet is fully or partially unmatched it can be adjusted and cancelled in the normal course.

In the past, unmatched bets were automatically cancelled when a market was suspended at the ‘off’ of the relevant event. With the "Keep bet" and "take SP" option you can now choose to either have your unmatched Exchange bet convert to an SP bet when the market suspends at the start of the event, or to have the bet ‘persist’ when the event goes in-play .

• In order to convert your unmatched Exchange bet to an SP bet when the market suspends you should select the ‘At In-Play: Take SP’ option in the bet manager.
  If there is a non-runner in a win market with a reduction factor of at least 2.5%, or a non-runner in a place market with a reduction factor of at least 4%, it is Betfair’s policy to cancel unmatched lay bets on all other runners in the market. In the case of any such non-runner, a lay bet for which the ‘At In-Play: Take SP’ option has been selected, will automatically convert to an SP bet. After this conversion the bet cannot be cancelled.
  Otherwise, unlike an SP bet, you can choose to cancel an Exchange bet once it has been placed, even if you have chosen for the bet to persist or to convert to an SP bet at the start of the event.
  If you choose to convert an unmatched Exchange lay bet to an SP bet, the liability of your Exchange lay bet will be converted into a liability for the SP bet. Your liability for that SP bet will never be more than the liability for the Exchange bet you had specified. However, the amount you can win on the SP lay bet will differ from the amount you would have won had the Exchange bet been matched, depending on the final SP.
  
  
• For markets that are scheduled to be turned in-play at the ‘off’, a customer can request that an unmatched Exchange bet should not be cancelled when the market is turned in-play. This is done by selecting the ‘At In-Play: Keep’ option in the bet manager and means that the unmatched bet persists when other unmatched bets are cancelled at the start of the event.
  When a non-runner is removed from a horseracing market it is Betfair’s policy to cancel unmatched offers to lay all other horses in the market if the non-runner has a reduction factor of 2.5% or greater for win markets, or 4.0% or greater for place markets. In these circumstances offers to lay a horse with the ‘At In-Play: Keep’ option selected will not be cancelled. Instead the lay odds offered or requested in place markets will be reduced in proportion with the reduction factors of any non-runner(s) and the same will apply in win markets providing the relevant non-runner has a reduction factor of at least 2.5%.
  For the avoidance of doubt this means that (for example) when a event (goal, penalty or a red card) occurs in a soccer match and other unmatched bets are cancelled before the market is reopened, a ‘keep’ bet will not be cancelled.
  Please also note that for horseracing markets reduction factors are not applied to ‘keep’ bets which are matched in-play. In the event of a late withdrawal, Betfair reserves the right to remove the runner after completion of the race. In this case any ‘keep’ bet placed before the off and matched in-play will remain at the original selected price and will not be adjusted or cancelled as would be the case if the non-runner were removed pre-race.