Exposure is the worst-case scenario liability for each market, i.e. the greatest loss of funds the customer may incur based on any possible market settlement, held by Betfair to ensure the customer has sufficient funds come settlement time.
So these funds are is still in your account, it’s just not available for you to bet again until it is no longer needed to cover your potential liability in that market.
Multiple bets on the same market adjust the exposure whenever a subsequent bet is placed and, exposure can be reduced/released as a result of an opposing bet.
Unlike a traditional Bookmaker, a Betting Exchange holds the customer’s exposure on a market rather than debiting each individual bet from their total account balance (Account Balance).
This is required to accommodate functions unique to a Betting Exchange such as the placing and editing of unmatched bets, and the trading on markets by placing Back and Lay bets on opposing selections. At all times, a customer’s exposure is subtracted from their Account Balance to form their balance that is available for bet placement (Cash Balance).
The Cash Balance is viewable at the top of all customer interfaces and is an accurate representation on how much money the customer has available to spend. It’s not until market settlement that the Account Balance itself, as viewable in the Account Statement, is credited or debited with the final settlement value.