Methods, systems, and articles of manufacture are disclosed for determining payers of cost events in a billing environment. A biller may provide billable services or goods for its customers. At least one participant may be involved in rendering the services or goods, or a service or good related thereto. The payer for each invoice may be determined depending on one or more factors, such as the type of service or good provided and/or the relationships between the involved participant. Additional features may be provided, such as issuing an invoice to the identified payer to request payment.