Competition between service providers is believed to improve market efficiency. On the other hand, fragmentation of expensive resources, e.g., spectrum for wireless services, between providers can introduce inefficiencies in resource utilisation and worsen overall system performance. In such cases, resource pooling among the independent service providers can be used to improve overall system performance. For providers to agree upon resource pooling in competitive environments, it has to be

beneficial to all of them. However, the traditional notion of resource pooling, which implies full sharing, need not have this property. For example, with full pooling, one of the providers may be worse off and hence have no incentive to share. We propose the bounded overflow partial resource sharing model as a generalization of full pooling and which has the feature of sharing that is beneficial to all participants. Here each provider contributes a fraction of its resources to a common pool which can be used all the providers.

We formally define and analyze the bounded overflow model, for two service providers, each of which is an Erlang-B loss system with the blocking probabilities as the performance measure. We show that there always exist partial sharing configurations that are beneficial to both providers independently of the load and the number of circuits of each of the providers. A key result is that the Pareto frontier has at least one of the providers sharing all its resources in the common pool. Furthermore, full pooling may not lie inside this Pareto set. The choice of the sharing configurations within the Pareto set is formalized based on bargaining theory. Another key result is that both the Kalai-Smorodinsky and the egalitarian solutions are unique in spite of the non-convexity of the utility set. Finally, large system approximations of the blocking probabilities in the quality-efficiency-driven regime are presented.