From a theory viewpoint, the use of auctions with zero public reserve prices also called absolute auctions, or the use of auctions with secret reserve prices is somehow puzzling despite being common. By allowing that buyers differ in their processing of past data regarding how the participation...

With exogenous participation, strong bidders should be discriminated against weak bidders to maximize revenues (Myerson 1981). When participation is endogenous and the set of potential entrants is large, optimal discrimination if any takes a very different form. Without incumbents, there should...

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...

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...

In the symmetric independent private value model, we revisit auctions with entry by adding two additional ingredients: difficulties to commit to the announced mechanism, in particular not to update the reserve price after bidders took their entry decisions, and seller's ex ante uncertainty on...

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...