Abstract: An electronic transaction processing system comprising an inbound payment processing module, an outbound payment processing module, an authorization module, and a data store containing financial account data relating to an entity. The authorization module is arranged to authorize processing of outbound payments by the outbound payment processing module, the financial account data defines a currency amount corresponding to working capital of the entity, inbound payments processed by the inbound payment processing module are added to said currency amount, and authorized outbound payments processed by the outbound payment processing module are removed from said currency amount.