We consider robust virtual implementation, where robustness is the requirement that implementation succeed in all type spaces consistent with a given payoff type space as well as with a given space of first-order beliefs about the other agents’ payoff types. This last bit, which constitutes...

We study the role of whistleblowing in the following inspection game. Two agents who compete for a prize can either behave legally or illegally. After the competition, a controller investigates the agents' behavior. This inspection game has a unique Bayesian equilibrium in mixed strategies. We...

In many markets, homogenous goods and services are sold both by large global frms and small local frms. Surprisingly, the large frms charge, often substantially, higher prices. Examples include hotels, airlines, and coffee shops. This paper provides a parsimonious model that can account for...

Mechanisms where sellers set the price and are charged a linear commission fee are widely used by real world intermediaries, e.g. by real estate brokers. Empirically these commission fees exhibit very little variance, both across heterogeneous regional markets and over time. So far, there is no...

We consider general asset market environments in which agents with quasilinear payoffs are endowed with objects and have demands for other agents' objects. We show that if all agents have a maximum demand of one object and are endowed with at most one object, the VCG transfer of each agent is...

Mechanisms where intermediaries charge a commission fee and have the sellers set the price are widely used in practice e.g. by real estate agents, stock brokers, art galleries, or auction houses. We model competition between intermediaries in a dynamic random matching model, where in every...

We analyze the competitive e?ects of backward vertical integration by a partially vertically integrated ?rm that competes with non-integrated ?rms both upstream and downstream. We show that vertical integration is procompetitive under fairly general conditions. It can be anticompetitive only if...

Mechanisms according to which private intermediaries or governments charge transaction fees or indirect taxes are prevalent in practice. We consider a setup with multiple buyers and sellers and two-sided independent private information about valuations. We show that any weighted average of...

This paper estimates the cost of using simple percentage fees rather than the broker optimal Bayesian mechanism, using data for real estate transactions in Boston in the mid-1990s. This counterfactual analysis shows that interme- diaries using the best percentage fee mechanisms with fees ranging...

We derive the optimal incentive compatible and individually rational mechanisms to reallocate arbitrary given ownership shares among a set of agents. These mechanisms are optimal in the sense that they maximize social surplus of the final allocation subject to the aforementioned constraints and...