Stock market overreactions to bad news in good times: a rational expectations equilibrium model

This article presents a dynamic, rational expectations equilibriummodel of asset prices where the drift of fundamentals (dividends)shifts between two unobservable states at random times. I showthat in equilibrium, investors' willingness to hedge againstchanges in their own 'uncertainty' on the true state makes stockprices overreact to bad news in good times and underreact togood news in bad times. I then show that this model is betterable than conventional models with no regime shifts to explainfeatures of stock returns, including volatility clustering,'leverage effects,' excess volatility, and time-varying expectedreturns.     

The information content of implied volatilities and model-free volatility expectations: Evidence from options written on individual stocks

We measure the volatility information content of stock options for individual firms using option prices for 149 US firms and the S&P 100 index. We use ARCH and regression models to compare volatility forecasts defined by historical stock returns, at-the-money implied volatilities and model-free volatility expectations for every firm. For 1-day-ahead estimation, a historical ARCH model outperforms both of the volatility estimates extracted from option prices for 36% of the firms, but the option forecasts are nearly always more informative for those firms that have the more actively traded options. When the prediction horizon extends until the expiry date of the options, the option forecasts are more informative than the historical volatility for 85% of the firms. However, at-the-money implied volatilities generally outperform the model-free volatility expectations.     

Rational expectations equilibrium with uncertain proportion of informed traders

This paper introduces uncertainty regarding the proportion of informed traders in a rational expectation equilibrium model with asymmetric information. The proportion uncertainty dramatically changes the properties of the resulting equilibrium. First, it may generate multiple nonlinear rational expectations equilibria, which can help explain the excessive volatility of stock prices. Second, the expected price informativeness is a non-monotonic function of the proportion of informed traders, which suggests that the traders will have more incentive to become informed as the proportion of informed traders gets larger.     

Option pricing model with sentiment

In this paper, we develop a closed-form option pricing model with the stock sentiment and option sentiment. First, the model shows that the price of call option is amplified by bullish stock sentiment, and is reduced by stock bearish sentiment, and the price of put option is in the opposite situation. Second, the price of call option is more sensitive to bullish stock sentiment; the price of put option is more sensitive to bearish stock sentiment. Third, the price of call option increases substantially with respect to the stock sentiment and the option sentiment. The price of put option decreases substantially with respect to the stock sentiment, increases substantially with respect to the option sentiment. Fourth, our models also reveal that the option volatility smile is steeper (flatter) when the stock sentiment becomes more bearish (bullish). Finally, stock sentiment and option sentiment lead to the option price deviating from the rational price. The model could offer a partial explanation of some option anomalies: option price bubbles and option volatility smile.     

A description of farmland investor expectations

We consider how best to characterize agricultural real estate market participants' expectation formation mechanism. The expectation formation mechanism links current agricultural policies to asset prices and tells us how current policies change expectations for future transfers. We examine behavior of real estate prices and returns using the present value model. We derive estimable equations incorporating two rival expectation formation mechanisms: rational and adaptive expectations. Assuming rational expectations, the present value model yields parameter estimates that imply the model should be rejected. Instead of rejecting the present value model while maintaining the rational expectations hypothesis, we let the data reveal which expectations hypothesis best fits the data. When we assume the rival hypothesis, the model yields parameter estimates that conform to adaptive expectations.     

Stock Market Volatility and Learning

We show that consumption‐based asset pricing models with time‐separable preferences generate realistic amounts of stock price volatility if one allows for small deviations from rational expectations. Rational investors with subjective beliefs about price behavior optimally learn from past price observations. This imparts momentum and mean reversion into stock prices. The model quantitatively accounts for the volatility of returns, the volatility and persistence of the price‐dividend ratio, and the predictability of long‐horizon returns. It passes a formal statistical test for the overall fit of a set of moments provided one excludes the equity premium.     

Estimation of an adaptive stock market model with heterogeneous agents

Standard asset pricing models based on rational expectations and homogeneity have problems explaining the complex and volatile nature of financial markets. Recently, boundedly rational and heterogeneous agent models have been developed and simulated returns are found to exhibit various stylized facts, such as volatility clustering and fat tails. Here, we are interested in how well the proposed models can explain all the properties seen in real data, not just one or a few at a time. Hence, we do a proper estimation of some simple versions of such a model by the use of efficient method of moments and maximum likelihood and compare the results to real data and more traditional econometric models. We discover two main findings. First, the similarities with observed data found in earlier simulations rely crucially on a somewhat unrealistic modeling of the noise term. Second, when the stochastic is more properly introduced the models are still able to generate some stylized facts, but the fit is generally quite poor.     

Rational expectations and corporate dividend policy

The problem of expectations formation has been either ignored or treated with very restrictive assumptions in traditional dividend adjustment models. Since these models are typically used to explain the dividend decisions of individual firms, a more satisfactory treatment of the process of expectations formation is needed. In order to analyze the dynamic dividend adjustment process, this article proposes a model, more general than previous ones, that is consistent with the rational expectations hypothesis. A nonlinear regression method is used to estimate the parameters of the model and to test the validity of the rational expectations hypothesis in dividend decisions making. The partial adjustment model with rational expectations explains dividend adjustments reasonably well. The overall results suggest that firms make use of available earnings information to form optimal future earnings forecasts; specifically, a firm's dividend adjustment process is completed in about two and a half quarters. This article also finds that the fourth-order serial correlation problem disappears after a generalized Tobit model is used for the parameter estimation.     

Heterogeneous expectations and long-range correlation of the volatility of asset returns

Inspired by the recent literature on aggregation theory, we attempt to relate the long-range correlation of the stock return volatility to the heterogeneity of the investors' expectations concerning the level of the future volatility. Based on a semi-parametric model of investors' anticipations, we make the connection between the distributional properties of the heterogeneity parameters and the auto-covariance/auto-correlation functions of the realized volatility. We report different behaviors, or change of convention, the observation of which depends on the market phase under consideration. In particular, we report and justify the fact that the volatility exhibits significantly longer memory during phases of a speculative bubble than during the recovery phase following the collapse of a speculative bubble.     

Adaptive expectations, underparameterization and the Lucas critique

A striking implication of the replacement of adaptive expectations by rational expectations was the “Lucas critique,” which showed that expectation parameters, and endogenous variable dynamics, depend on policy parameters. We consider this issue from the vantage point of bounded rationality, where for transparency we model bounded rationality by means of simple adaptive expectations. We show that for a range of processes, monetary policy remains subject to the Lucas critique. However, there are also regimes in which the expectation parameter is locally invariant and the Lucas critique does not apply.     

Stock return expectations in the credit market

In this paper we compute long-term stock return expectations (across the business cycle) for individual firms using information backed out from the credit derivatives market. Our methodology builds on previous theoretical results in the literature on stock return expectations and, empirically, we demonstrate a close relationship between credit-implied stock return expectations and future realized stock returns. We also find stock portfolios selected based on credit-implied stock return forecasts to beat equally- and value-weighted portfolios of the same stocks out-of-sample. Contrary to many other studies, our expectations/predictions are made at the individual stock level rather than at the portfolio level, and no parameter estimations using historical stock price- or credit spread observations are needed.     

Oil Price and Stock Market Synchronization in Gulf Cooperation Council Countries

Knowing that the Gulf Cooperation Council (GCC) economies are dichotomous in nature, and growth in the non-oil sector is tributary to the oil sector, we document the extent of synchronization between crude oil prices and stock markets for each of the GCC markets and for the GCC as an economic bloc. We use both the bivariate and multivariate nonparametric synchronicity measures proposed by Mink et al. (2007) to assess that linkage. We find a low to mild (mild to strong) degree of synchronization between oil price and stock market returns (volatilities). In a very few instances, we find very strong (above 80 percent) associations between these variables. These results hold irrespective of whether we assume that stock market participants form adaptive or rational expectations about the price of oil. Dynamic factor results confirm that shocks to volatility are more important than shocks to oil price returns for the GCC stock markets.     

Rational expectations and the effectiveness of monetary policy with special reference to the Barro-Fischer model

Monetary policy is sometimes alleged to be ineffective when the rational-expectations hypothesis is imposed on macroeconomic models. Barro and Fischer (1976) once presented in this journal a simple macroeconomic model in order to explain such a claim. However, their conclusion depends on a specific rule employed for the future course of money supply. It is shown that their model embodies an important factor which generally renders monetary policies effective, rational expectations notwithstanding. It is suggested that this property also holds in more general macroeconomic frameworks.     

Rational expectations and the dynamic structure of macroeconomic models: A critical review

This paper surveys critically the literature on rational expectations and the dynamic structure of macroeconomic models. The theoretical framework common to this literature is set forth for the reader unfamiliar with it. As this is done, problems are brought out which are usually ignored in existing literature. The topics discussed are: (1) rational expectations and the natural rate hypothesis. (2) optimal linear forecasts and their applications, (3) the general linear rational expectations model and its use in econometric policy evaluation, and (4) information and convergence problems in rational expectations models.     

Rational expectations and the smoothing properties of inventories of finished goods

This paper formulates and estimates a dynamic rational expectations equilibrium model of inventories of finished goods and employment of labor. The view that the primary role of inventories of finished goods is to act as a buffer stock in the face of fluctuating demand is examined. Both the model and estimation results indicate that this is the case because of differences in the costs involved for firms in changing their inventory stocks and labor force. In addition to providing some new evidence on the behavior of inventories of finished goods and employment, the paper illustrates a technology for maximum-likelihood estimation of structural parameters under the hypothesis of rational expectations.     

SENSITIVITY OF INVESTOR REACTION TO MARKET DIRECTION AND VOLATILITY: DIVIDEND CHANGE ANNOUNCEMENTS

We examine whether investor reactions are sensitive to the recent direction or volatility of underlying market movements. We find that dividend change announcements elicit a greater change in stock price when the nature of the news (good or bad) goes against the grain of the recent market direction during volatile times. For example, announcements to lower dividends elicit a significantly greater decrease in stock price when market returns have been up and more volatile. Similarly, announcements to raise dividends tends to elicit a greater increase in stock price when market returns have been normal or down and more volatile, although this latter tendency lacks statistical significance. We suggest an explanation for these results that combines the implications of a dynamic rational expectations equilibrium model with behavioral considerations that link the responsiveness of investors to market direction and volatility.     

Does more information in stock price lead to greater or smaller idiosyncratic return volatility?

We investigate the relation between price informativeness and idiosyncratic return volatility in a multi-asset, multi-period noisy rational expectations equilibrium. We show that the relation between price informativeness and idiosyncratic return volatility is either U-shaped or negative. Using several price informativeness measures, we empirically document a U-shaped relation between price informativeness and idiosyncratic return volatility. Our study therefore reconciles the opposing views in the following two strands of literature: (1) the growing body of research showing that firms with more informative stock prices have greater idiosyncratic return volatility, and (2) the studies arguing that more information in price reduces idiosyncratic return volatility.     

Inventories,rational expectations,and the business cycle

The simplest macroeconomic models in which markets clear instantaneously, and expectations are rational preclude the existence of ‘business cycles’, that is, of serially correlated deviations of output from trend. This paper studies one of several mechanisms that can be used to make these so-called ‘new-classical’ models produce business cycles; the mechanism is the gradual adjustment of inventory stocks. Two macroeconomic models of inventory holdings are formulated. Both imply, first, that current output should be a decreasing function of the stock of inventories and, second, that inventories, once perturbed from equilibrium levels, should adjust only gradually. These two features are then embedded into an otherwise standard macroeconomic model in which markets clear instantaneously and expectations are rational. Two principal conclusions are reached. First, disturbances such as unanticipated changes in money will set in motion serially correlated deviations of output from trend. Second, if desired inventories are sensitive to the real interest rate, then even fully anticipated changes in money can affect real variables.     

A note on non-uniqueness in rational expectations models

McCallum has proposed a solution procedure for rational expectations models - undetermined coefficients with the minimal set of state variables - which can avoid the non-uniqueness problem. This procedure often requires some additional restrictions on the admissible values of the structural parameters. In this note we show that in some cases, these parameter restrictions may be defended with less ambiguity by considering the dynamics of the model, rather than examining particular parameter values, as suggested by McCallum.     

The Impact of Trades on Daily Volatility

This article proposes a trading-based explanation for the asymmetriceffect in daily volatility of individual stock returns. Previousstudies propose two major hypotheses for this phenomenon: leverageeffect and time-varying expected returns. However, leveragehas no impact on asymmetric volatility at the daily frequencyand, moreover, we observe asymmetric volatility for stocks withno leverage. Also, expected returns may vary with the businesscycle, that is, at a lower than daily frequency. Trading activityof contrarian and herding investors has a robust effect on therelationship between daily volatility and lagged return. Consistentwith the predictions of the rational expectation models, thenon-informational liquidity-driven (herding) trades increasevolatility following stock price declines, and the informed(contrarian) trades reduce volatility following stock priceincreases. The results are robust to different measures of volatilityand trading activity. (JEL C30, G11, G12)