This short paper shows that in an affiliated value setting one more bidder at the auction stage need not induce a higher expected welfare in either ascending price or second price auctions. We highlight the roles of asymmetries between bidders and of the multidimensional character of the private...

Standard Bayesian models assume agents know and fully exploit prior distributions over types. We are interested in modeling agents who lack detailed knowledge of prior distributions. In auctions, that agents know priors has two consequences: (i) signals about own valuation come with precise...

This paper considers an auction design framework in which bidders get partial feedback about the distribution of bids submitted in earlier auctions: either bidders are asymmetric but past bids are disclosed in an anonymous way or several auction formats are being used and the distribution of...

We study multi-object auctions where agents have private and additive valuations for heterogeneous objects. We focus on the revenue properties of a class of dominant strategy mechanisms where a weight is assigned to each partition of objects. The weights influence the probability with which...

We study the effects of allocative and informational externalities in (multi-object) auctions and related mechanisms. Such externalities naturally arise in models that embed auctions in larger economic contexts. In particular, they appear when there is downstream interaction among bidders after...