Auctioning Horizontally Differentiated Items

This paper analyzes competition between two sellers that offer horizontally differentiated items at competing auctions. Three possible outcomes can arise in equilibrium. For substantially differentiated items the monopoly reserve prices form an equilibrium, and the market is not entirely covered. When products become closer substitutes, a non-empty interval of types becomes valuable to both sellers. When transport costs are low, and virtual valuations are high, sellers compete for these bidders and set their reserve prices below the valuation of the marginal bidder. In equilibrium all types enjoy participation rents. For intermediate levels of transport costs it is not worth competing for runaway bidders. In this case, there is a continuum of equilibria. In each equilibrium sellers adjust their reserve prices so that the marginal bidder gets no rents.