Traders with short horizons and privately known trading limits interact in a market for a risky asset. Risk-averse, long horizon traders supply a downward sloping residual demand curve that face the short-horizon traders. When the price falls close to the trading limits of the short horizon traders, selling of the risky asset by any trader increases the incentives for others to sell. Sales become mutually reinforcing among the short term traders, and payoffs analogous to a bank run are generated. A “liquidity black hole” is the analogue of the run outcome in a bank run model. Short horizon traders sell because others sell. Using global game techniques, this paper solves for the unique trigger point at which the liquidity black hole comes into existence. Empirical implications include the sharp V-shaped pattern in prices around the time of the liquidity black hole.
One role of monetary policy is to coordinate expectations in the economy and greater transparency of monetary policy may lead to greater coordination. But if transparent monetary policy helps coordinate expectations, then it must also magnify mistakes.
JEL Classification: C7, E5
Keywords: Communication, monetary policy, transparency, common knowledge
In a financial market where traders are risk averse and short lived, and prices are noisy, asset prices today depend on the average expectation today of tomorrow’s price. Thus (iterating this relationship) the date 1 price equals the date 1 average expectation of the date 2 average expectation of the date 3 price. This will not in general equal the date 1 average expectation of the date 3 price. We show how this failure of the law of iterated expectations for average belief can help understand the role of higher order beliefs in a fully rational asset pricing model and explain over-reaction to (noisy) public information.
Incomplete information games, local interaction games and random matching games are all special cases of a general class of interaction games (Morris (1997)). In this paper, we use this equivalence to present a unified treatment of arguments generating uniqueness in games with strategic complementarities by introducing heterogeneity in these different settings. We also report on the relation between local and global heterogeneity, on the role of strategic multipliers and on purification in the three types of interaction game.
In a simple model of currency crises caused by creditor coordination failure, we show that bailouts that reduce ex post inefficiency will sometimes create ex ante moral hazard but will sometimes enhance the incentives for governments to take preventative actions. This model helps us understand a debate about the role of the IMF in catalyzing lending to developing countries.
Keywords: Moral hazard, Financial crisis, International financial architecture, Global games
What are the welfare effects of enhanced dissemination of public information through the media and disclosures by market participants with high public visibility? For instance, is it always desirable to have frequent and timely publications of economic statistics by government agencies and the central bank? We examine the impact of public information in a setting where agents take actions appropriate to the underlying fundamentals, but they also have a coordination motive arising from a strategic complementarity in their actions. When the agents have no private information, greater provision of public information always increases welfare. However, when agents also have access to independent sources of information, the welfare effect of increased public disclosures is ambiguous.
Global games are games of incomplete information whose type space is determined by the players each observing a noisy signal of the underlying state. With strategic complementarities, global games often have a unique, dominance solvable equilibrium, allowing analysis of a number of economic models of coordination failure. For symmetric binary action global games, equilibrium strategies in the limit (as noise becomes negligible) are simple to characterize in terms of ‘diffuse’ beliefs over the actions of others. We describe a number of economic applications that fall in this category. We also explore the distinctive roles of public and private information in this setting, review results for general global games, discuss the relationship between global games and a literature on higher order beliefs in game theory and describe the relationship to local interaction and dynamic games with payoff shocks.
Keywords: Global games, common knowledge, unique equilibrium, currency crises, bank runs and liquidity
Are beliefs as indeterminate as auggested by models with multiple equilibria? Multiplicity of equilibria arise largely as the unintended consequence of two modelling assumptions — the fundamentals are assumed to be common knowledge, and economic agents know others’ actions in equilibrium. Both are questionable. When others’ actions are not known with certainty, such as when actions rely on noisy signals, self-fulfilling beliefs lead to a unique outcome determined by the fundamentals and the knowledges that others are rational. This paper illustrates this approach in the context of a model of bank runs and other similar applications. Such an approach places comparative statics and policy analyses on a firmer footing. It also suggests that public information has a disproportionately larger impact on the outcome than private information.
Keywords: Multiple equilibria, macroeconomics, common knowledge
Creditors of a distressed borrower face a coordination problem. Even if the fundamentals are sound, fear of premature foreclosure by others may lead to pre-emptive action, undermining the project. Recognition of this problem lies behind corporate bankruptcy provisions across the world, and it has been identified as a culprit in international financial crises, but has received scant attention from the literature on debt pricing. The apparent multiplicity of equilibria is a barrier to development of this issue in asset pricing, but this multiplicity is only apparent. Without common knowledge of fundamentals, the incidence of failure is uniquely determined provided that private information is precise enough. This affords a way to price the coordination failure. There are two further conclusions. First, coordination is more difficult to sustain when fundamentals deteriorate. Thus, when fundamentals deteriorate,t he onset of crisis can be very swift. Second, “transparency” — in the sense of greater provision of information to the market — does not generally mitigate the coordination problem. Transparency is not a panacea.
The swiftness and devastating impact of recent financial crises have taken many market participants by surprise, and pose challenges for economists seeking a theory of the onset of a crisis. We propose such a theory based on two features. The actions of diverse economic actors which undermine the currency are mutually reinforcing, while the fragmented nature of the media create small disparities in their information. In such circumstances, the beliefs of market participants can be tracked in the same way as the economic fundamentals, and an attack is triggered when the economic fundamentals deteriorate sufficiently to fall below the minimum level of market confidence necessary to support the currency. We give a characterization of such a minimum level of confidence.