We study a notion of locally robust implementation that captures the idea that the planner may know agentsʼ beliefs well, but not perfectly. Locally robust implementation is a weaker concept than ex-post implementation, but we show that no regular allocation function is locally robust...

We analyse the interplay between license auctions and market structure in a model with several incumbents and several potential entrants. The focus is on the competitiveness induced by the number of auctioned licences. Moreover, we study how the auction format affects the incentives for explicit...

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 a model that involves identity-dependent, asymmetric negative external effects. Willingness to pay, which can be computed only in equilibrium, will reflect, besides private valuations, also preemptive incentives stemming from the desire to minimize the negative externalities. We find...

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...

Europe has taken the global lead in the issuance of third generation (3G) licences for mobile telecommunications according to the UMTS/IMT-2000 family of standards. We survey the recent European UMTS licence auctions and compare their outcomes with the predictions of a simple auction model that...

The consumption of an indivisible good causes identity-dependent externalities to non-consumers. We analyse resale markets where the current owner designs the trading procedure, but cannot commit to future actions. We ask the following questions. (1) Does the identity of the initial owner matter...

The sensitivity of Bayesian implementation to agents' beliefs about others suggests the use of more robust notions of implementation such as ex post implementation, which requires that each agent's strategy be optimal for every possible realization of the types of other agents. We show that the...

The authors study the strategic equilibria of a negotiation game where potential buyers are affected by identity-dependent, negative externalities. The unique equilibrium of long, finitely repeated generic games can either display delay--where a transaction can take place only in several stages...