Abstract: A system for conducting a commercial transaction between a buyer and a seller is disclosed. The system includes a transaction processing system for facilitating payment for a transaction between the buyer and the seller. In addition to the buyer and the seller, the transaction processing system also interacts with an issuer and an acquirer. The issuer issues and manages an account for the buyer. The acquirer manages an account for the seller. The transaction processing system operates as follows. An electronic invoice relating to the transaction is first posted to the system by the seller or another system. Upon accepting the electronic invoice, the system creates a payment instruction. Each time a payment instruction is created, the system applies certain pre-negotiated payment terms and conditions between the buyer and the seller to the payment instruction. After the payment instruction is created, the system seeks approval from the buyer.