Research

Publications

Robust Auctions with Affiliated Private Values, accepted at Review of Economic Design, 2024. 

Abstract:  We study auctions in an affiliated private value framework in which buyers face ambiguity over the distribution of the others’ valuations and make choices that are robust to that ambiguity. We show that, in contrast to the Bayesian case, a first-price auction can generate a higher revenue than a second-price auction in the presence of ambiguity. We also extend this insight to large double auctions. In particular, we propose a pay-as-bid double auction mechanism and demonstrate that given any nontrivial amount of ambiguity, this mechanism implements the efficient trade and is ex-post budget balanced with probability one as the market size grows.

Intertemporal Hedging and Trade in Repeated Games with Recursive Utility, joint with Asen Kochov,  Econometrica, 2023.

Abstract: Two key features distinguish the general class of recursive preferences from the standard model of dynamic choice: (i) agents may care about the intertemporal distribution of risk, and (ii) their rates of time preference, rather than being fixed, may vary with the level of consumption. We investigate what these features imply in the context of a repeated strategic interaction. First, we show that opportunities for intertemporal trade may expand the set of feasible payoffs relative to that in a static interaction. Two distinct sources for such trade are identified: endogenous heterogeneity in the players' rates of time preference and a hedging motivepertaining to the intertemporal distribution of risk. The set of equilibrium payoffs may on the other hand shrink drastically as many efficient outcomes become unsustainable no matter the level of patience. This “antifolk” result occurs when the players prefer stage outcomes to be positively correlated rather than independent across time. Intuitively, such preferences make it inefficient to offset short‐term losses with future gains, while this is needed to ensure that security levels are met on path. We also establish a folk theorem: if security levels are met on path, such play can be sustained in a subgame perfect equilibrium provided that the players are sufficiently patient.

Approximate Bayesian Implementation and Exact Maxmin Implementation: An Equivalence, Games and Economic Behavior, 2023. 

Abstract: This paper provides a micro-foundation for approximate incentive compatibility using ambiguity aversion. In particular, we propose a novel notion of approximate interim incentive compatibility, approximate local incentive compatibility, and establish an equivalence between approximate local incentive compatibility in a Bayesian environment and exact interim incentive compatibility in the presence of a small degree of ambiguity. We then apply our result to the implementation of efficient allocations. In particular, we identify two economic settings—including ones in which approximately efficient allocations are implementable and ones in which agents are informationally small—in which efficient allocations are approximately locally implementable when agents are Bayesian. Applying our result to those settings, we conclude that efficient allocations are exactly implementable when agents perceive a small degree of ambiguity.

Public Goods with Ambiguity in Large Economies, joint with Narayana Kocherlakota, Journal of Economic Theory, 2019. 

Abstract: We consider a canonical problem in economics: the financing and provision of a public good. Mailath and Postlewaite (1990) show that under natural information and enforcement frictions, the probability of providing the public good falls to zero as the population size goes to infinity even if provision of the public good is efficient. In this paper, we allow agents to have multiple prior beliefs about others' valuations and to make choices that reflect their aversion to that ambiguity. We show that, as long as each agent's set of priors contains some distribution of valuations under which provision is inefficient, it is possible to find a mechanism in large economies that finances provision of the public good.

Efficient Implementation with Interdependent Valuations and Maxmin Agents, Journal of Economic Theory, 2018.

Abstract: We consider a single object allocation problem with multidimensional signals and interdependent valuations. When agents' signals are statistically independent, Jehiel and Moldovanu (2001) show that efficient and Bayesian incentive compatible mechanisms generally do not exist. In this paper, we extend the standard model to accommodate maxmin agents and obtain necessary as well as sufficient conditions under which efficient allocations can be implemented. In particular, we derive a condition that quantifies the amount of ambiguity necessary for efficient implementation. We further show that under some natural assumptions on the preferences, this necessary amount of ambiguity becomes sufficient. Finally, we provide a definition of informational size such that given any nontrivial amount of ambiguity, efficient allocations can be implemented if agents are sufficiently informationally small. 

Working Papers

Risk and Monotone Comparative Statics without Independence, joint with Collin Raymond, 2024. 

Folk Theorem with Unobservable Mixtures under Endogenous Discounting,  joint with Asen Kochov, 2024