Patent ID: 8301539

Claim:
A system for electronically trading securities, the system comprising: a communications interface that is configured to receive orders that are electronically tradable; and a processing system that is coupled to the communications interface, the processing system including at least one processor, the processing system configured to: receive, via the communications interface, an order request from a client system, the order request including an order to be executed and an execution priority parameter that is selected by a user of the client system; determine an execution priority from among a plurality of predetermined execution priorities based on the execution priority parameter selected by the user; execute the order against a plurality of contra side quotes/orders of market participants in accordance with the determined execution priority, wherein the determined execution priority determines, at least in part, which among the plurality of contra side quotes/orders the order is executed against, wherein the order is a first order, the execution priority is a first execution priority, the execution priority parameter is a first execution priority parameter, and the processing system is further configured to: receive, via the communications interface, second order request, the second order request including a second order to be executed and a second execution priority parameter that is different from the first execution priority parameter; determine a second execution priority from among the plurality of redetermined execution priorities based on the second execution priority parameter, the second execution priority different than the first execution priority; execute the second order against a second plurality of contra side quotes/orders of market participants; and in accordance with the execution of the second order, determine, based on the determined second execution priority, at least one contra side quote/order of the second plurality of the contra side quotes/orders to fulfill the second order, the least one contra side quote/order being different than another at least one contra side quote/order of the second plurality of contra side quotes/orders if the first execution priority had been used in the execution of the second order.