Competing Auctions with Heterogeneous Goods

This paper studies a model of competing auctions in which bidders attach different valuations to the items offered by sellers. We provide a novel characterization of the set of (symmetric) participation rules used by bidders and show that contrary to models with homogeneous goods, heterogeneity rules out randomization when bidders choose trading partners. We also show that changes in some reserve price alter the participation decision of every buyer regardless of her valuation of the item. This implies that such changes not only affect the distribution of valuations of those buyers participating in a given auction but also modify the probability with which every buyer visits the auctions.