An improved system and method is provided for making markets for a finite subset of orders across continuous and countably infinite outcome spaces. To do so, a prediction market engine may be provided to support prediction markets by aggregating information about orders specifying a continuous subspace of a continuous outcome space and orders specifying a subset of a countably infinite set of outcomes. The pricing and/or quantities for orders received may be determined, a response may be sent to traders indicating the pricing or quantities of orders for payment, and the amount owed for accepted orders may be collected. Winning accepted orders may be identified and payout may be made for winning accepted orders. Advantageously, the present invention may support aggregation of more information from market participants in a prediction market to forecast the likelihood of the occurrence of a certain event.