Corporate governance and game theoretic analyses of shareholder power: the case of Spain

The definition and implementation of control is at the heart of the corporate governance debate. The paper approaches the issue by using power indices derived from the theory of cooperative games. An application to Spanish listed firms shows that incentives for large shareholders to form controlling blocs are high. In the Spanish system of corporate governance ownership concentration is therefore the main mechanism to mitigate agency problems between shareholders and managers. Moreover, these results suggest that the Shapley–Shubik index is not an appropriate measure of shareholder power.     

Existence of Nash equilibria in finite extensive form games with imperfect recall: A counterexample

This paper provides an example showing that for finite extensive form games without perfect recall existence of Nash equilibria in behaviour strategies is not guaranteed in general.     

Conditional behavior and learning in similar stag hunt games

This paper reports an experiment using Stag Hunt games with different payoff ranges. Specifically, in one treatment for half of the games the payoff dominant and the risk dominant equilibrium coincide and for the other half of the games they conflict; in the second treatment they always conflict. The experiment provides evidence that the payoff range experienced by the participant influences the likelihood of efficient conventions emerging. In particular, experiencing games where payoff dominance and risk dominance coincide appears to make payoff dominance more attractive in games in which they conflict. In the experiment, we also observe conditional behavior emerging with experience. We develop a model of conditional expectations to explain these stylized facts that depends crucially on the assumption that after a brief learning period participants categorize their experience using the same relative bandwidth in both treatments even though the range of experience is twice as large in treatment 1 as it is in treatment 2. The assumption cannot be rejected by the data. The analysis provides a formal example in which increasing experienced diversity by changing the way similar experiences are categorized increases the likelihood of efficient conventions emerging in communities playing similar Stag Hunt games.     

Network externalities in consumer spending on lottery games: evidence from Spain

We use data from two nationally representative Spanish surveys in 2005 and 2006 to investigate spending on lottery games. Estimates from Tobit and double hurdle models of participation in lottery markets and spending on lottery tickets find that frequent participation in one game is not associated with an increased or decreased probability of participating in other games, but is associated with increased spending on other games. Consumer spending on different lottery games exhibits inter-related consumption decisions. Also, the assumptions underlying the double hurdle model, but not the Tobit model, better describe consumer spending on lottery tickets in Spain.     

Dynamic collusion in an open economy

This paper provides an example of how opening a country to trade may decrease competition in an industry. This result, counter to conventional theory, occurs when one considers multi-period games.     

Fault tolerance in large games

A Nash equilibrium is an optimal strategy for each player under the assumption that others play according to their respective Nash strategies, but it provides no guarantees in the presence of irrational players or coalitions of colluding players. In fact, no such guarantees exist in general. However, in this paper we show that large games are innately fault tolerant. We quantify the ways in which two subclasses of large games – λ-continuous games and anonymous games – are resilient against Byzantine faults (i.e. irrational behavior), coalitions, and asynchronous play. We also show that general large games have some non-trivial resilience against faults.     

On the limit perfect public equilibrium payoff set in repeated and stochastic games

This paper provides a dual characterization of the existing ones for the limit set of perfect public equilibrium payoffs in a class of finite stochastic games (in particular, repeated games) as the discount factor tends to one. As a first corollary, the folk theorems of Fudenberg et al. (1994), Kandori and Matsushima (1998) and Hörner et al. (2011) obtain. As a second corollary, it is shown that this limit set of payoffs is a convex polytope when attention is restricted to perfect public equilibria in pure strategies. This result fails for mixed strategies, even when attention is restricted to two-player repeated games.     

Strategic knowledge sharing in Bayesian games

This paper provides a model for the study of direct, public and strategic knowledge sharing in Bayesian games. We propose an equilibrium concept which takes into account communication possibilities of exogenously certifiable statements and in which beliefs off the equilibrium path are explicitly deduced from consistent possibility correspondences, without making reference to perturbed games. Properties of such an equilibrium and of revised knowledge are examined. In particular, it is shown that our equilibrium is always a sequential equilibrium of the associated extensive form game with communication. Finally, sufficient conditions for the existence of perfectly revealing or non-revealing equilibria are characterized in some classes of games. Several examples and economic applications are investigated.     

Star-shapedness of Richter-Aumann integral on a measure space with atoms: theory and economic applications

This paper provides sufficient (as well as necessary) conditions for the integral of a correspondence defined on a measure space with atoms to exhibit star-shaped values. This result is used to analyze the existence of a Nash equilibrium in games with a measure space of agents with atoms and of a competitive equilibrium in economies with mixed markets. In either case it is shown that an exact equilibrium exists whenever atoms are “small enough”.     

Aggregate comparative statics

In aggregative games, each playerʼs payoff depends on her own actions and an aggregate of the actions of all the players. Many common games in industrial organization, political economy, public economics, and macroeconomics can be cast as aggregative games. This paper provides a general and tractable framework for comparative static results in aggregative games. We focus on two classes of games: (1) aggregative games with strategic substitutes and (2) nice aggregative games, where payoff functions are continuous and concave in own strategies. We provide simple sufficient conditions under which positive shocks to individual players increase their own actions and have monotone effects on the aggregate. The results are illustrated with applications to public good provision, contests, Cournot competition and technology choices in oligopoly.     

Generalized potentials and robust sets of equilibria

This paper introduces generalized potential functions of complete information games and studies the robustness of sets of equilibria to incomplete information. A set of equilibria of a complete information game is robust if every incomplete information game where payoffs are almost always given by the complete information game has an equilibrium which generates behavior close to some equilibrium in the set. This paper provides sufficient conditions for the robustness of sets of equilibria in terms of argmax sets of generalized potential functions. These sufficient conditions unify and generalize existing sufficient conditions. Our generalization of potential games is useful in other game theoretic problems where potential methods have been applied.     

Pillage and property

This paper introduces a class of coalitional games, called pillage games, as a model of Hobbesian anarchy. Any coalition can pillage, costlessly and with certainty, any less powerful coalition. Power is endogenous, so a pillage game does not have a characteristic function, but pillage provides a domination concept that defines a stable set, which represents an endogenous balance of power. Every stable set contains only finitely many allocations, and can be represented as a farsighted core. Additional results are obtained for particular games, including the game in which the power of each coalition is determined by its total wealth.     

Political economy with affect: On the role of emotions and relationships in political economics

This paper discusses and provides experimental evidence on the role of emotions and, in particular, the neglected role of endogenous affective relationships (bonding) in three key areas of political economy: (i) appropriation, with compliance or resistance as response; (ii) competition for access to appropriation and its potential for escalation and de-escalation of the inherent conflict; and (iii) determinants of (large scale) collective action. To that purpose, a series of experiments on power-to-take games and public good games are presented and put into perspective. Furthermore, the relevance of an affective social ties model for explaining these experimental findings is investigated. Finally, some important political economic implications are addressed.     

Adaptive learning in extensive form games and sequential equilibrium

Summary. This paper studies adaptive learning in extensive form games and provides conditions for convergence points of adaptive learning to be sequential equilibria. Precisely, we present a set of conditions on learning sequences such that an assessment is a sequential equilibrium if and only if there is a learning sequence fulfilling the conditions, which leads to the assessment. Received: November 5, 1996; revised version: May 28, 1997     

Fictitious play in 2×2 games: A geometric proof of convergence

Summary This paper provides a new proof of Miyasawa's (1961) result showing the convergence of fictitious play in 2×2 games. The novelty of the approach used here is that it rests entirely on the geometric properties of the best-response correspondence. The geometric approach greatly shortens the exposition, and it suggests some possible extensions to more difficult convergence conjectures.We thank Glenn Ellison, Vijay Krishna, Eric Maskin and an anonymous referee for helpful comments. This paper was written while Metrick was supported by an NSF Graduate Fellowship and Polak was supported by a Junior Fellowship in the Society of Fellows at Harvard University.     

Modelling International Policy Games: Lessons from European Monetary Coordination

Most international monetary policy games are modelled as prisoners' dilemma games. Political scientists suggest however that other game-theoretic structures (chicken, stag-hunt and deadlock games) could be more appropriate to describe international monetary coordination. This paper provides some empirical evidence on this issue, by studying the case of European monetary coordination from 1979 to 1989. First, central banks' and governments' preferences are revealed through an analysis of their actual behaviour. Then, the dynamic game describing policymakers' interactions is simulated under alternative institutional arrangements: coordination, defection, sub-group coalitions, etc. The main conclusion is that the stylised facts derived from those experiments seem not to be consistent with the implications of the prisoners' dilemma framework. Consistency is instead found with the features of a stag-hunt game. CEPR and FEEM This revised version was published online in July 2006 with corrections to the Cover Date.     

Stochastic evolutionary stability in extensive form games of perfect information

Nöldeke and Samuelson [Games Econ. Behav. 5 (1993) 425] investigate a stochastic evolutionary model for extensive form games and show that even for games of perfect information with a unique subgame perfect equilibrium, non-subgame perfect equilibrium-strategies may well survive in the long run even when mutation rates tend to zero. In a different model of evolution in the agent normal form of these games Hart [Games Econ. Behav. 41 (2002) 227] shows that under suitable limit-taking, where small mutation rates are accompanied by large population sizes in a particular way, the unique prediction is again the subgame perfect equilibrium. This paper provides a proof of a similar result for the model of Nöldeke and Samuelson.     

Testing Employment Determination in Unionised Economies as a Repeated Game

This paper is an empirical analysis of alternative bargaining theories of wage and employment determination. Using data from manufacturing sectors of the Spanish economy, we find that unions and firms are not myopic and take dynamic considerations into account in the bargaining process. This work is an empirical test of the bargaining model in Espinosa and Rhee (1989) and provides support for their conclusions.     

Learning in games with strategic complementarities revisited

Fictitious play is a classical learning process for games, and games with strategic complementarities are an important class including many economic applications. Knowledge about convergence properties of fictitious play in this class of games is scarce, however. Beyond games with a unique equilibrium, global convergence has only been claimed for games with diminishing returns [V. Krishna, Learning in games with strategic complementarities, HBS Working Paper 92-073, Harvard University, 1992]. This result remained unpublished, and it relies on a specific tie-breaking rule. Here we prove an extension of it by showing that the ordinal version of strategic complementarities suffices. The proof does not rely on tie-breaking rules and provides some intuition for the result.     

A NEW MULTIPLICATIVE DECOMPOSITION FOR THE FOSTER–GREER–THORBECKE POVERTY INDICES

This paper shows that Foster–Greer–Thorbecke poverty indices can be written as the product of components summarizing the incidence, intensity and inequality dimensions of poverty and provides an empirical illustration of the decomposition using Spanish household budget surveys data.