When bidders are not substitutes, we show that there is no standard ascend-ing auction that implements a bidder-optimal competitive equilibrium under truthful bidding. Such an impossibility holds also in environments where the Vickrey payoff vector is a competitive equilibrium payoff and is thus...

Brendstrup (2007) and Brendstrup and Paarsch (2006) claim that sequential English auction models with multi-unit demand can be identified from the distribution of the last stage winning price and without any assumption on bidding behavior in the earliest stages. We show that their identification...

This paper considers the implementation of an economic outcome under complete information when the strategic and informational details of the participation game are partially-specified. This means that full participation is required to be a subgame-perfect equilibrium for a large variety of...

We consider standard auction models when bidders' identities are not observed by the econometrician. First, we adapt the definition of identifiability to a framework with anonymous bids and we explore the extent to which anonymity reduces the possibility to identify private value auction models....

The analysis of second price auctions with externalities is utterly modified if the seller is unable to commit not to participate in the mechanism. For the General Symmetric Model introduced by Milgrom and Weber [P. Milgrom, R. Weber, A theory of auctions and competitive bidding, Econometrica 50...

We consider standard auction models when bidders' identities arenot observed by the econometrician. First, we adapt the denition ofidentiability to a framework with anonymous bids and we explore theextent to which anonymity reduces the possibility to identify privatevalue auction models. Second,...

We introduce contingent auction mechanisms, which is a supersetof combinatorial auctions, and where bidders submit bids on packagesthat are contingent on the whole nal assignment. Without externalities,the Vickrey and the Ausubel-Milgrom Proxy Auction areboth robust if items are perceived as...

The literature on ascending combinatorial auctions yields conflicting insights regarding the possibility to implement the Vickrey payoffs for general valuations. We introduce the class of minimal ascending auctions, a class which allows one to disconnect the final payments from the final bids...