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Johannes Hörner Publications

Publish Date
Abstract

This paper characterizes an equilibrium payoff subset for Markovian games with private information as discounting vanishes. Monitoring is imperfect, transitions may depend on actions, types be correlated and values interdependent. The focus is on equilibria in which players report truthfully. The characterization generalizes that for repeated games, reducing the analysis to static Bayesian games with transfers. With correlated types, results from mechanism design apply, yielding a folk theorem. With independent private values, the restriction to truthful equilibria is without loss, except for the punishment level; if players withhold their information during punishment-like phases, a “folk” theorem obtains also.

Abstract

This paper characterizes an equilibrium payoff subset for dynamic Bayesian games as discounting vanishes. Monitoring is imperfect, transitions may depend on actions, types may be correlated and values may be interdependent. The focus is on equilibria in which players report truthfully. The characterization generalizes that for repeated games, reducing the analysis to static Bayesian games with transfers. With independent private values, the restriction to truthful equilibria is without loss, except for the punishment level; if players withhold their information during punishment-like phases, a folk theorem obtains.

Abstract

This paper provides a dual characterization of the limit set of perfect public equilibrium payoffs in stochastic games (in particular, repeated games) as the discount factor tends to one. As a first corollary, the folk theorems of Fudenberg, Levine and Maskin (1994), Kandori and Matsushima (1998) and Hörner, Sugaya, Takahashi and Vieille (2011) obtain. As a second corollary, in the context of repeated games, it follows that this limit set of payoffs is a polytope (a bounded polyhedron) when attention is restricted to equilibria in pure strategies. We provide a two-player game in which this limit set is not a polytope when mixed strategies are considered.

Abstract

This paper develops a model of career concerns. The worker’s skill is revealed through output, wage is based on expected output, and so on assessed ability. Specifically, effort increases the probability that a skilled worker achieves a one-time breakthrough. Effort levels at different times are strategic substitutes. Equilibrium effort (and, if marginal cost is convex, wage) is single-peaked with seniority. The agent works too little, too late. Both delay and underprovision of effort worsen if effort is observable. If the firm commits to wages but faces competition, the optimal contract features piecewise constant wages as well as severance pay.

Abstract

This paper analyzes the impact of market structure on career concerns. Effort increases the probability that a skilled agent achieves a one-time breakthrough. Wages are based on assessed ability and on expected output. For any wage, the agent works too little, too late. Under short-term contracts, effort and wages are single-peaked with seniority, due to the strategic substitutability of effort levels at different times. Both delay and underprovision of effort worsen if effort is observable. Commitment to wages by competing firms mitigates these inefficiencies. In that case, the optimal contract features piecewise constant wages and severance pay.

Abstract

We investigate the role of market transparency in repeated first-price auctions. We consider a setting with private and independent values across bidders. The values are assumed to be perfectly persistent over time.

We analyze the first-price auction under three distinct disclosure regimes regarding the bid and award history. Of particular interest is the minimal disclosure regime, in which each bidder only learns privately whether he won or lost the auction at the end of each round. In equilibrium, the winner of the initial auction lowers his bids over time, while losers keep their bids constant, in anticipation of the winner’s lower future bids. This equilibrium is efficient, and all information is eventually revealed. Importantly, this disclosure regime does not give rise to pooling equilibria.

We contrast the minimal disclosure setting with the case in which all bids are public, and the case in which only the winner’s bids are public. In these settings, an inefficient pooling equilibrium with low revenues always exists with a sufficiently large number of bidders.

Abstract

We investigate the role of market transparency in repeated first-price auctions. We consider a setting with independent private and persistent values. We analyze three distinct disclosure regimes regarding the bid and award history. In the minimal disclosure regime each bidder only learns privately whether he won or lost the auction. In equilibrium the allocation is efficient and the minimal disclosure regime does not give rise to pooling equilibria. In contrast, in disclosure settings where either all or only the winner’s bids are public, an inefficient pooling equilibrium with low revenues exists.

Abstract

We investigate the role of market transparency in repeated first-price auctions. We consider a setting with independent private and persistent values. We analyze three distinct disclosure regimes regarding the bid and award history. In the minimal disclosure regime each bidder only learns privately whether he won or lost the auction. In equilibrium the allocation is efficient and the minimal disclosure regime does not give rise to pooling equilibria. In contrast, in disclosure settings where either all or only the winner’s bids are public, an inefficient pooling equilibrium with low revenues exists.

Abstract

This paper brings mechanism design to the study of conflict resolution in international relations. We determine when and how unmediated communication and mediation reduce the ex ante probability of conflict, in a simple game where conflict is due to asymmetric information. Unmediated communication helps reducing the chance of conflict as it allows conflicting parties to reveal their types and establish type-dependent transfers to avoid conflict. Mediation improves upon unmediated communication when the intensity of conflict is high, or when asymmetric information is large. The mediator improves upon unmediated communication by not precisely reporting information to conflicting parties, and precisely, by not revealing to a player with probability one that the opponent is weak. Surprisingly, in our set up, arbitrators who can enforce settlements are no more effective in reducing the probability of conflict than mediators who can only make non-binding recommendations.

Abstract

We examine the buyer-seller problem under different levels of commitment. The seller is informed of the quality of the good, which affects both his cost and the buyer’s valuation, but the buyer is not. We characterize the allocations that can be achieved through mechanisms in which, unlike with full commitment, the buyer has the option to “walk away” after observing a given offer. We further characterize the equilibrium payoffs that can be achieved in the bargaining game in which the seller makes all the offers, as the discount factor goes to one. This allows us to identify how different levels of commitment affect outcomes, and which constraints, if any, preclude efficiency.

Abstract

This paper solves for the set of equilibrium payoffs in bargaining with interdependent values when the informed party makes all offers, as discounting vanishes. The seller of a good is informed of its quality, which affects both his cost and the buyer’s valuation, but the buyer is not. To characterize this payoff set, we derive an upper bound, using mechanism design with limited commitment. We then prove that this upper bound is tight, by showing that all its extreme points are equilibrium payoffs. Our results shed light on the role of different forms of commitment on the bargaining process. In particular, we show that it is the buyer’s inability to commit to a contract before observing the terms of trade that precludes efficiency.

Abstract

We study a dynamic buyer-seller problem in which the good is information and there are no property rights. The potential buyer is reluctant to pay for information whose value to him is uncertain, but the seller cannot credibly convey its value to the buyer without disclosing the information itself. Information comes as divisible hard evidence. We show how and why the seller can appropriate a substantial fraction of the value through gradual revelation, and how the entire value can be extracted with the help of a mediator.