Speculative bubbles,crashes and rational expectations

Self ending speculative bubbles, i.e., speculative bubbles followed by market crashes, are consistent with the assumption of rational expectations. More generally, speculative bubbles may take all kinds of shapes. Detecting their presence or rejecting their existence is likely to prove very hard.     

Confident expectations, rational expectations and the optimal conduct of monetary policy

Under what conditions central banks can afford to deviate from announced targets without losing their reputation is analyzed. For this, the public must have something like ‘confident expectations' vis-a-vis monetary policy and central banks have to behave accordingly. The paper shows that it can be rational for the public and welfare-increasing for the society to retain ‘confident expectations' instead of switching to rational expectations, when central banks have gained long-run reputation. At the end of the paper, alternative optimal money supply rules are compared in a dynamic optimization framework. © 1998 Elsevier Science B.V. All rights reserved.     

Interest-rate policy and rational expectations

The choice of monetary instrument under rational expectations is discussed in a general equilibrium model for the financial sector. It is shown that a supply rule leads to indeterminate asset prices, whereas the prices are determinate under an appropriately formulated interest-rate policy.     

Understanding Markov-switching rational expectations models

We develop a set of necessary and sufficient conditions for equilibria to be determinate in a class of forward-looking Markov-switching rational expectations models and we develop an algorithm to check these conditions in practice. We use three examples, based on the new-Keynesian model of monetary policy, to illustrate our technique. Our work connects applied econometric models of Markov-switching with forward looking rational expectations models and allows an applied researcher to construct the likelihood function for models in this class over a parameter space that includes a determinate region and an indeterminate region.     

On non-revealing rational expectations equilibrium

It is shown that a non-revealing rational expectations equilibrium may not be coalitionally Bayesian incentive compatible, may not be implementable as a perfect Bayesian equilibrium and may not belong to the weak fine core and thus may not be fully Pareto optimal. These negative results lead us to conclude the non-revealing rational expectations equilibrium is not a sensible solution concept. We wish to thank Dr A. Hadjiprocopis for his invaluable help with the implementation of Latex in a Unix environment. We also thank a referee for several, constructive suggestions.     

Competitive equilibrium hyperinflation under rational expectations

This paper shows that a competitive equilibrium model, where a representative agent maximizes welfare, expectations are rational and markets are in equilibrium can account for several hyperinflation stylized facts. The theory is built by combining two hypotheses, namely, a fiscal crisis that requires printing money to finance an increasing public deficit and a predicted change in an unsustainable fiscal regime.We thank an anonymous referee for very helpful comments. A. B. Cunha acknowledges financial support from the Brazilian Council of Science and Technology (CNPq).     

On multiple equilibria and the rational expectations hypothesis

Summary This paper analyzes through a simple two-period model the fact that, if some agents hold inside money intertemporally, the second-period normalization matters. Thus, there are several equilibria of the second-period economy, indexed by the level of inflation. A concept of equilibrium acknowledging this fact, and requiring that agents put some weight on any of the possible second-period equilibrium price vectors is developed. Such an equilibrium is shown to exist, and is illustrated by an example.This a revised version of chapter three of my Ph.D. dissertation. I would like to thank David Cass, Atsushi Kajii, George Mailath and Shinichi Suda for helpful discussions and comments. Thanks are also due to Jean-Michel Grandmont who pointed out mistakes in a previous version. All remaining mistakes are of course my own. Financial support from a CARESS scholarship at the University of Pennsylvania is gratefully acknowledged.     

Money demand, the Cagan model, testing rational expectations vs adaptive expectations: The case of Turkey

This paper estimates the Cagan type demand for money function for Turkish economy during the period 1986:1–1995:3 and tests whether Cagan's specification fits the Turkish data using an econometric technique assuming that forecasting errors are stationary. This paper also tests the hypothesis that monetary policy was implemented in aiming to maximize the inflation tax revenue. Finally, the Cagan model is estimated with the additional assumption of rational expectations for Turkey for the considered period. First version received: March 1998/final version received: October 1998     

Learning rational expectations in an asset market

Will traders in a risky asset market learn Muthian expectations when they initially lack the necessary information? If some traders learn from their observations, will market dynamics depend only on “fundamentals,” as implied by the Efficient Market Hypothesis? This paper shows that at any finite point in time the answer to these questions is “no”. The context is a constant absolute risk aversion model with two kinds of traders and asymmetric information. The market converges asymptotically to a rational expectations equilibrium where prices depend only on fundamentals and the market is efficient.     

Functional rational expectations equilibria in market games

The rational expectations equilibrium (REE) has been criticized as an equilibrium concept in market game environments. Such an equilibrium may not exist generically, or it may introduce unrealistic assumptions about an economic agent’s knowledge or computational ability. We define an REE as a probability measure over uncertain states of nature which exploits all available information in a market game, and which exists for almost all economies. Furthermore, if retrading is allowed, it is possible for agents to compute such a ‘functional rational expectations equilibrium’ using straightforward numerical fixed point algorithms. The approach is demonstrated in a detailed numerical example.     

Monetary non-neutrality with anticipatory price setting and rational expectations

It is proved that the neutrality proposition for anticipated monetary policy fails, when markets do not continuously clear and prices partly adjust in accordance with rationally anticipated disequilibrium. The model exhibits non-uniqueness, but all solutions are non-neutral.     

On multiple equilibria and the rational expectations hypothesis?

Summary. This paper analyzes through a simple two-period model the fact that, if some agents hold inside money intertemporally, the second-period “normalization” matters. Thus, there are several equilibria of the second-period economy, indexed by the level of inflation. A concept of equilibrium acknowledging this fact, and requiring that agents put some weight on any of the possible second-period equilibrium price vectors is developed. Such an equilibrium is shown to exist, and is illustrated by an example.     

Decision making on pension schemes under rational expectations

In this paper the formation of expectations during decision making processes on pension schemes is the main focus. An overlapping generations model is used where politicians control the tax-transfer system and the young determine savings. No generation of decision makers is committed to previous decisions. It appears that the outcome in the stationary state depends on the efficiency of the tax-transfer system compared with savings and on the preferences of politicians relative to young individuals with respect to the division of endowments between young-age and old-age consumption. One of the main conclusions is that if the parameters of the system are constant the stationary state enters within a finite time interval. So, if the system is initially outside the stationary state, the decision makers can calculate the path of taxes and savings towards the stationary state. This feature is also used to determine the effects of a demographic change.Comments from Dieter Bös, Fons Groot, Lex Meijdam, Willem Thorbecke, and David Wildasin are gratefully acknowledged. All remaining errors are, of course, ours.     

The effectiveness of monetary reform under rational expectations

Automatic monetary stabilizers based on interest rate information are analyzed in a rational expectations framework. Their impact on price level variability is studied, and their effectiveness is compared to optimal decentralized monetary instruments.     

The government behavioural constraint in rational expectations models

Models with rational expectations typically include state variables whose values are controlled by the government. Hence, the need to specify behavioural rules for the authorities. Our purpose is to show, in the context of a well-known Cagan type model of the demand for money, that the assumption of rational expectations imposes the hitherto neglected requirement of rationality of the postulated behaviour of government. In particular the occurance of non-unique solutions highlights the need for a rational choice between these on grounds other than mathematical convenience or ad hoc economic assumptions of minimum variance, terminal conditions etc.     

Learning rational expectations: The finite state case

This paper is devoted to the question of whether traders can learn rational expectations from repeated observations of market data in a stationary environment with finitely many exogenous states of the world. The learning problem is placed in the context of an iterative adjustment process which achieves equilibrium if traders have rational expectations. The main result is that even if traders begin with no knowledge of their environment, there exists an estimation procedure which converges to rational expectations when the environment satisfies a certain regularity condition. The regularity condition is shown to be generic.