A computer-implemented method for processing single message transactions with batch settlement may include receiving a dual-message transaction from a merchant, converting the received dual-message transaction to a single-message transaction, setting a flag on the converted single-message transaction indicating the conversion to a single-message transaction, receiving a batch settlement file from the merchant, for each transaction in the batch settlement file, determining whether the single-message transaction conversion flag is set, upon determining that the single-message transaction conversion flag is not set, storing the transaction for later processing, and upon determining that the single-message transaction conversion flag is set, sending the transaction to a payment network.