A computer system that provides pooled computing resources to clients may receive requests for resources, each of which includes a bid amount. While the supply of resources exceeds the demand, the system may adaptively determine a theoretical bid threshold for the resource pool that represents the predicted value of the lowest bid amount for which corresponding requests will be granted when demand for the resources exceeds supply. The determination may be dependent on a distribution of the bid amounts included in the requests for resources. The system may adaptively determine the lowest bid amount for which corresponding ones of the requests will be granted during non-contention dependent on changes in demand for the resources, the total capacity of the resource pool, and the theoretical bid threshold value, and may grant requests that include higher bid amounts. The use of some resources may be terminated in response to changes in demand.