How store format choices and market structure affect agglomeration economies and competition among chain stores in the US supermarket industry

This article studies how store format choices and market concentration affect agglomeration economies and competition among chain stores. Using data on supermarket chains in Arizona, Georgia and Illinois, we decompose a store’s sales into parts stemming from local market conditions, such as demographics, and parts stemming from competition measures, which can be of its own chain’s stores or of other chains’ stores. Our results show that local market conditions are still a key factor in generating store sales. In more concentrated markets of Georgia and Illinois, a supermarket chain suffers from business-stealing among its own stores – agglomeration economies not sufficient to offset competition among its stores – but ironically tolerates the presence of other chains’ stores. Can a retail chain favourably tip the balance of agglomeration economies and competition? We find the answer by looking at the two big corporations in Arizona – Bashas Markets Inc. and Kroger Co. – which own two and three store formats, respectively, catering to distinct consumer segments, and thus promoting agglomeration economies while minimizing competition among their own stores.