A model of market-making

The two essential features of a decentralized economy taken into account are, first, that individual agents need some information about other agents in order to meet potential trading partners, which requires some communication or interaction between these agents, and second, that in general agents will face trading uncertainty. We consider trade in a homogeneous commodity. Firms decide upon their effective supplies, and may create their own markets by sending information signals communicating their willingness to sell. Meeting of potential trading partners is arranged in the form of shopping by consumers. The questions to be considered are: How do firms compete in such markets? And what are the properties of an equilibrium? We establish existence conditions for a symmetric Nash equilibrium in the firms' strategies, and analyze its characteristics. The developed framework appears to lend itself well to study many typical phenomena of decentralized economies, such as the emergence of central markets, the role of middlemen, and price-making.Decentralized trade, market--making, communication, trading uncertainty, Leex

Truthful Revelation Mechanisms for Simultaneous Common Agency Games

In games in which multiple principals contract simultaneously and non-cooperatively with the same agent, standard direct revelation mechanisms in which the agent reports his type(i.e. his exogenous private information) have been proven inadequate to characterize the entire set of equilibrium outcomes. This paper introduces a more general class of revelation mechanisms in which the agent reports also the contractual decisions he is inducing with the principals. We …rst show that such a class has the same nice properties as the class of all unrestricted menus: (i) for any equilibrium of any indirect game with arbitrary communication space for the principals, there exists a truthful equilibrium in the game in which the principals are restricted to o¤er revelation mechanisms that sustains the same outcomes; (ii) any truthful equilibrium is robust in the sense that it remains an equilibrium in any game in which the principalsstrategy space is enlarged. We next show how revelation mechanisms can be put to work in applications such as menu auctions, moral hazard settings, and competition in non-linear tariffs to identify necessary and sufficient conditions for the sustainability of outcomes as common agency equilibria.mechanism design, contracts, Revelation Principle.

Nash Codes for Noisy Channels

This paper studies the stability of communication protocols that deal with transmission errors. We consider a coordination game between an informed sender and an uninformed decision maker, the receiver, who communicate over a noisy channel. The sender's strategy, called a code, maps states of nature to signals. The receiver's best response is to decode the received channel output as the state with highest expected receiver payoff. Given this decoding, an equilibrium or "Nash code" results if the sender encodes every state as prescribed. We show two theorems that give sufficient conditions for Nash codes. First, a receiver-optimal code defines a Nash code. A second, more surprising observation holds for communication over a binary channel which is used independently a number of times, a basic model of information transmission: Under a minimal "monotonicity" requirement for breaking ties when decoding, which holds generically, EVERY code is a Nash code.Comment: More general main Theorem 6.5 with better proof. New examples and introductio

Information Transmission in Nested Sender-Receiver Games

We introduce a “nestedness” relation for a general class of sender-receiver games and compare equilibrium properties, in particular the amount of information transmitted, across games that are nested. Roughly, game is nested in game if the players’s optimal actions are closer in game. We show that under some conditions, more information is transmitted in the nested game in the sense that the receiver’s expected equilibrium payoff is higher. The results generalize the comparative statics and welfare comparisons with respect to preferences in the seminal paper of Crawford and Sobel (1982). We also derive new results with respect to changes in priors in addition to changes in preferences. We illustrate the usefulness of the results in three applications: (i) delegation to an intermediary with a different prior, the choice between centralization and delegation, and two-way communication with an informed principal

Mediation in Situations of Conflict and Limited Commitment

We study the reasons and conditions under which mediation is beneficial when a principal needs information from an agent to implement an action. Assuming a strong form of limited commitment, the principal may employ a mediator who gathers information and makes non-binding proposals. We show that a partial rev-elation of information is more effective through a mediator than through the agent himself. This implies that mediation is strictly helpful if and only if the likelihood of a conflict of interest is positive but not too high. The value of mediation depends non-monotonically on the degree of conflict. Our insights extend to general models of contracting with imperfect commitment