Bubbles and Self-fulfilling Crises

Financial crises are often associated with an endogenous credit reversal followed by a fall in asset prices and serious disruptions in the financial sector. To account for this sequence of events, this paper constructs a model where the excessive risk-taking of portfolio investors leads to a bubble in asset prices (in the spirit of Allen and Gale, 'Bubbles and Crises', Economic Journal, 2000), and where the supply of credit to these investors is endogenous. We show that the interplay between the risk shifting problem and the endogeneity of credit may give rise multiple equilibria associated with di¤erent levels of lending, asset prices, and output. Stochastic equilibria lead, with positive probability, to an ine¢ cient liquidity dry-up at the intermediate date, a market crash, and widespread failures of borrowers. The possibility of multiple equilibria and self-fulfilling crises is showed to be related to the severity of the risk shifting problem in the economyCredit market imperfections, self-fulfilling expectations, financial crises.

Public spending shocks in a liquidity-constrained economy

This paper analyses the effect of transitory increases in government spending when public debt is used as liquidity by the private sector. Aggregate shocks are introduced into an incomplete-market economy where heterogenous, infinitely-lived households face occasionally binding borrowing constraints and store wealth to smooth out idiosyncratic income fluctuations. Debt-financed increases in public spending facilitate self-insurance by bond holders and may crowd in private consumption. The implied higher stock of liquidity also loosens the borrowing constraints faced by firms, thereby raising labour demand and possibly the real wage. Whether private consumption and wages actually rise or fall ultimately depends on the relative strengths of the liquidity and wealth effect that are produced by the shockborrowing constraints ; public debt ; fiscal policy shocks

Produce or Speculate? Asset Bubbles, Occupational Choice and Efficiency

We study the macroeconomic effects of rational asset bubbles in an overlapping-generations economy where asset trading requires specialized intermediaries and where agents freely choose between working in the production or in the financial sector. Frictions in the market for deposits create rents in the financial sector that affect workers' choice of occupation. When rents are large, the private gains associated with trading asset bubbles may lead too many workers to become speculators, thereby causing rational bubbles to lose their efficiency properties. Moreover, if speculation can be carried out by skilled labor only, then asset bubbles displace skilled workers away from the productive sector and raise income and consumption inequalities.rational bubbles, occupational choice, dynamic efficiency

Risk Shifting, Asset Bubbles, and Self-fulfilling Crises.

Financial crisis are often associated with an endogenous credit reversal fol- lowed by a fall in asset prices and failures of financial institutions. To account for this sequence of events, this paper constructs a model where the excess risk-taking of portfolio investors leads to a bubble in asset prices (in the spirit of Allen and Gale, Economic Journal, 2000), and where the supply of credit to these investors is endogenous. First, we show that changes in the composition and riskiness of investors' portfolio as total lending varies may cause the ex ante return on loans to increase with the amount of total lending, thereby creating the potential for multiple (Pareto-ranked) equilibria associated with different levels of lending, asset prices, and output. We then embed this mechanism into a 3-period model where the low-lending equilibrium is selected with positive probability at the intermediate date. This event is associated with a inefficient liquidity dry-up, a market crash, and widespread failures of borrowers.Financial crises; Credit market imperfections; self-fulfilling expectations;

Bubbles and self-fulfilling crises

Financial crises are often associated with an endogenous credit reversal followed by a fall in asset prices and serious disruptions in the financial sector. To account for this sequence of events, this paper constructs a model where the excessive risk-taking of portfolio investors leads to a bubble in asset prices (in the spirit of Allen and Gale, "Bubbles and Crises", Economic Journal, 2000), and where the supply of credit to these investors is endogenous. We show that the interplay between the risk shifting problem and the endogeneity of credit may give rise multiple equilibria associated with different levels of lending, asset prices, and output. Stochastic equilibria lead, with positive probability, to an inefficient liquidity dry-up at the intermediate date, a market crash, and widespread failures of borrowers. The possibility of multiple equilibria and self-fulfilling crises is showed to be related to the severity of the risk shifting problem in the economy.credit market imperfections ; self-fulfilling expectations ; financial crises

Market microstructure, information aggregation and equilibrium uniqueness in a global game

Speculators contemplating an attack (e.g., on a currency peg) must guess the beliefs of other speculators, which they can do by looking at the stock market. As shown in earlier work, this information-gathering process may be destabilising by creating multiple equilibria. This paper studies the role played by the microstructure of the asset market in the emergence of multiple equilibria driven by information aggregation. To do so, we study the outcome of a two-stage global game wherein an asset price determined at the trading stage of the game provides an endogenous public signal about the fundamental that affects traders’ decision to attack in the coordination stage of the game. In the trading stage, placing a full demand schedule (i.e., a continuum of limit orders) is costly, but traders may use riskier (and cheaper) market orders, i.e., order to sell or buy a fixed quantity of assets unconditional on the execution price. Price execution risk reduces traders aggressiveness and hence slows down information aggregation, which ultimately makes multiple equilibria in the coordination stage less likely. In this sense, microstructure frictions that lead to greater individual exposure (to price execution risk) may reduce aggregate uncertainty (by pinning down a unique equilibrium outcome)

L'étude des fluctuations macroéconomiques est-elle « scientifique » ?

L'étude des fluctuations macroéconomiques part du principe que le comportement du tout (les agrégats) ne se réduit pas à la somme des parties (les agents, les marchés). Il en est ainsi parce que les interdépendances entre marchés peuvent substantiellement amplifier, ou au contraire amortir, les chocs qui à tout moment perturbent l'équilibre. La compréhension de ces effets d'équilibre général, sur lesquels les évidences directes sont limitées, les facteurs confondants multiples, et les expérimentations contrôlées impossibles, est nécessairement plus conjecturale – mais non moins « scientifique » – que l'étude des comportements individuels ou d'un marché isolé. Ignorer ces effets au motif qu'ils n'ont pas le même degré de certitude empirique qu'un effet microéconomique directement observé peut conduire à de lourdes erreurs de politique économique

Market composition and price informativeness in a large market with endogenous order types

We analyse the joint determination of price informativeness and the composition of the market by order type in a large asset market with dispersed information. The market microstructure is one in which informed traders may place market orders or full demand schedules and where market makers set the price. Market-order traders trade less aggressively on their information and thus reduce the informativeness of the price; in a full market-order market, price informativeness is bounded, whatever the quality of tradersinformation about the assets dividend. When traders can choose their order type and demand schedules are (even marginally) costlier than market orders, then market-order traders overwhelm the market when the precision of private signals goes to innity. This is because demand schedules are substitutes: at high levels of precision, a residual fraction of demand-schedule traders is sufficient to take the trading price close to traders signals, while the latter is itself well aligned with the dividend. Hence, the gain from trading conditional on the price (as demand-schedule traders do) in addition to ones own signal (as all informed traders do) vanishes

Is the study of business-cycle fluctuations 'scientific?'

The study of macroeconomic fluctuations assumes that the behavior of the whole (aggregates) cannot be reduced to the sum of the parts (agents, markets). This is because interdependencies between markets can substantially amplify, or on the contrary dampen, shocks that at any time disturb the equilibrium. The understanding of general-equilibrium effects, on which direct evidence is limited, which are empirically blurred by multiple potential confounding factors, and for which controlled experiments are almost impossible to design, is necessarily more conjectural than the study of individual behavior or of a specific market. However, ignoring these effects because they do not have the same degree of empirical certainty as a directly observed microeconomic effect can lead to serious policy mistakes

Incomplete markets and the output-inflation tradeoff

This paper analyses the effects of money shocks on macroeconomic aggregates in a flexible-price, incomplete-markets environment that generates persistent wealth inequalities amongst agents. In this framework, unexpected money shocks redistribute wealth from the cash-rich employed to the cash-poor unemployed, and induce the former to increase their labour supply in order to maintain their desired levels of consumption and precautionary savings. The reduced-form dynamics of the model is a textbook "output-inflation tradeoff" equation whereby inflation shocks raise current output. The attenuating role of mean inflation and money growth persistence on this non-neutrality tradeoff, as well as some of the welfare implications of wealth redistribution, are also examined.incomplete markets ; borrowing constraints ; short-run nonneutrality