An authorization request for a payment transaction is obtained, from a given one of a plurality of billers, over a payment network having a standard clearing and settlement time period. Via the payment network, a special IOU approval authorization request response to the authorization request for the payment transaction is passed, indicating that the given one of the plurality of billers will be paid in connection with the payment transaction after expiration of a grace period from a time of the authorization request, regardless of whether funds are available for an account associated with the payment transaction. The grace period is longer than the standard clearing and settlement time period. The payment transaction is not settled until expiration of the grace period.