Allocating resources

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for allocating resources. In one aspect, a method includes receiving, from a resource requester, a first request statement specifying a first computing resource, a first bid for the first computing resource, a total quantity of the first resource requested by the resource requester; and a minimum quantity of the first resource that the resource requester is willing to accept. A second request statement can be received from the resource requester that specifies a second bid for the second computing resource and a condition statement specifying that the second bid is only valid if the first computing resource will be allocated to the resource requestor. A determination can be made that allocation of the second computing resource and at least the minimum quantity of the first resource to the resource requestor will achieve a resource allocation objective.