Abstract: A data processing system is disclosed that establishes and administers charge accounts, including both funded and post-funded accounts. In one embodiment, the system of the invention establishes charge accounts for all of the patients of a medical professional, with creditworthy patients having funded accounts, and patients who are not creditworthy having post-funded accounts. Each patient is issued a charge card which can be used to pay for medical services at participating providers. When a patient with a funded account charges medical services, the doctor is paid promptly and the servicing company proceeds to collect payment from the patient. For post-funded accounts, the doctor is not paid until funds are received from the patient.