We study contests where several privately informed agents bid for a price. All bidders bear a cost of bidding that is an increasing function of their bids, and, moreover, bids may be capped. We show that, regardless of the number of bidders, if agents have linear or concave cost functions then...

This paper discusses some economic aspects of the recent German and Austrian UMTS license auctions. We consider a stylized model of the open ascending auction with incomplete information and market externalities. It is shown that, if the dominant incumbent is not successful in pushing the...

We study efficient, Bayes-Nash incentive compatible mechanisms in a social choice setting that allows for informational and allocative externalities. We show that such mechanisms exist only if a congruence condition relating private and social rates of information substitution is satisfied. If...

We consider a social choice setting with multidimensional signals and interdependent valuations. Such frameworks have been recently and increasingly used in order to study multi-object auctions. We obtain concise characterizations of ex-post implementable (not necessarily efficient) social...

We analyze the possibility of efficient trade with informationally interdependent valuations and with a dispersed ownership. A crucial role is played by the sign of the derivatives that measure how valuation functions depend on others’ signals. If valuations are increasing functions of other...

In our framework, when a buyer does not obtain the auctioned object, he is no longer indifferent about the identity of the winner (i.e., eyternal effects are present). Buyer i's preferences are characterized by an N-dimensional vector t^i = (t1^i, t2^i,..,tN^i). The coordinate ti^i can be...

We consider an auction with risk neutral agents having independent private valuations for several heterogenous objects. Most of the literature on revenue-maximizing auctions has focused on the sale of one good or on the sale of several identical units (thus yielding one-dimensional informational...

We briefly survey several insights about value and revenue maximization in multi-object auctions and apply them to the German (and Austrian) UMTS auction. In particular, we discuss in detail the exposure probelm that caused firms in Germany to pay almost Euro 20 billion for nothing.

A contest architecture specifies how the prize sum is split among several prizes, and how the contestants (who are here privately informed about their abilities) are split among several sub-contests. We compare the performance of such schemes to that of grand winner-take-all contests from the...

An indivisible good can be consumed by one of several agents. The consumption involves identity-dependent externalities to non-consumers. Resale markets for such goods are analyzed in various institutional settings where agents cannot commit to future actions. We address the following questions:...