Online auctions with a fixed end-time often experience a sharp increase in bidding towards the end despite using a proxy-bidding format. We provide a novel explanation of this phenomenon under private values. We study a correlated private values environment in which the seller bids in her own...

In the standard independent private values (IPV)model, each bidder’s beliefs about the values of any other bidder is represented by a unique prior. In this paper we relax this assumption and study the question of auction design in an IPV setting characterized by ambiguity: bidders have an...