A Cross Sectional Analysis of the Excess Comovement of Stock Returns PDF Download

Author: Robin Marc Greenwood
Publisher:
ISBN:
Category :
Languages : en
Pages : 46

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In the presence of limits to arbitrage, cross-sectional variation in periodic investor demand should be related to the degree of comovement of returns. I exploit the unusual weighting system of the Nikkei 225 index in Japan to identify cross-sectional variation in periodic demand for index stocks. Relative to their weights in a value weighted index, some stocks in the Nikkei are overweighted by a factor of ten or more. Using overweighting as an instrument for the proportionality between demand shocks for index stocks, I find a strong positive relation between overweighting and the comovement of a stock with other stocks in the index, and a negative relationship between index overweighting and comovement with stocks outside of the index. Put simply, overweighted stocks have high betas. The results suggest that excess comovement of stock returns is a consequence of an institutionalized commonality in trading behavior, rather than inefficiencies related to the speed at which index stocks incorporate economy-wide information.

Author: Robin M. Greenwood
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Relative to their weights in a value-weighted index, a number of stocks in Japan's Nikkei 225 stock index are overweighted by a factor of 10 or more. I document a strong positive relation between overweighting and the comovement of a stock with other stocks in the Nikkei index, and a negative relationship between index overweighting and comovement with stocks outside of the index. The cross-sectional approach resolves endogeneity problems associated with event study demonstrations of excess comovement. A trading strategy that bets on the reversion of stock prices of overweighted stocks generates economic profits, confirming that the observed comovement patterns are excessive, and providing further evidence that comovement of stock returns can be a consequence of commonality in trading behavior.

Author: Nathan Sosner
Publisher:
ISBN:
Category :
Languages : en
Pages :

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In April 2000, 30 stocks were replaced in the Nikkei 225 Index. The unusually broad index redefinition allowed for a study of the effects of index-linked trading on the excess comovement of stock returns. A large increase occurred in the correlation of trading volume of stocks added to the index with the volume of stocks that remained in the index, and opposite results occurred for the deletions. Daily index return betas of the additions rose by an average of 0.45; index return betas of the deleted stocks fell by an average of 0.63. Theoretical predictions for changes in autocorrelations and cross-serial correlations of returns of index additions and deletions were confirmed. The results are consistent with the idea that trading patterns are associated with short-run excess comovement of stock returns.

Author: Nathan Sosner
Publisher:
ISBN:
Category :
Languages : en
Pages : 59

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In April 2000, in one day, 30 stocks were replaced in the Nikkei 225 index in Japan. We analyze the change in comovement of returns of stocks added to and deleted from the index with the returns of stocks remaining in the index. A simple model shows that upon inclusion into (deletion from) a stock index, stocks should begin to comove more (less) with the index, due to a change in their trading pattern. The empirical findings provide sound support for these predictions: In the sample, daily index betas of the added stocks rose by an average of 0.60, while the average beta of the deleted stocks fell by 0.71. Our results confirm additional predictions of the model for changes in R2, turnover, and the autocorrelation of returns upon index inclusion and deletion, and hold at daily, weekly and bi-weekly return horizons. Fundamentals based explanations fail to account for these findings. We conclude that correlated trading of index stocks causes excess comovement of stock returns. We argue that the distinct trading mechanism on the Tokyo Stock Exchange contributes to the significance and magnitude of our results.

Author: Honghui Chen
Publisher:
ISBN:
Category : Rate of return
Languages : en
Pages : 51

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Recent evidence of excessive comovement among stocks following index additions (Barberis, Shleifer, and Wurgler, 2005) and stock splits (Green and Hwang, 2009) challenges traditional finance theory. Based on a simple model, we show that the bivariate regressions relied upon in the literature often provide little or no information about the economic magnitude of the phenomenon of interest, and the coefficients in these regressions are very sensitive to time-variation in the characteristics of the return processes that are unrelated to excess comovement. Instead, univariate regressions of the stock return on the returns of the group it is leaving (e.g., non-S&P stocks) and the group it is joining (e.g., S&P stocks) reveal the relevant information. When we reexamine the empirical evidence using control samples matched on past returns and compute Dimson betas, almost all evidence of excess comovement disappears. The results in the literature are consistent with changes in the fundamental factor loadings of the stocks. One key element to understanding these striking results is that, in both the examples we study, the stocks exhibit strong returns prior to the event in question. We document the heretofore unknown empirical regularity that winner stocks exhibit increases in betas. Thus, much of the apparent excess comovement is just a manifestation of momentum.

Author: Roopak J. Shah
Publisher:
ISBN:
Category : Stocks
Languages : en
Pages : 138

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Author: Jarl G. Kallberg
Publisher:
ISBN:
Category :
Languages : en
Pages : 41

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This paper is an empirical investigation of the excess comovement of industry indexes in the U.S. stock market over the period January 1973 to December 2001. We define excess comovement as the correlation between two assets beyond what could be explained by fundamental factors. In our analysis, the fundamental factors are sector groupings and the three Fama-French factors. We then estimate excess comovement as the mean absolute correlation of residuals of univariate (OLS) or joint (FGLS) regressions of these fundamentals on industry returns. We show that excess unconditional comovement is surprisingly high (a lower bound of 0.134 and an upper bound of 0.357) and represents between 31% and 83% of the average raw absolute correlation. Excess comovement is also consistently significant across industries and over our entire sample interval. Furthermore, we find that the degree of excess comovement is symmetric, i.e., not significantly different in rising or falling markets. We explain approximately 21% of this excess correlation by its positive relation to market volatility, and reveal a negative relation of its lower bound to the level of the short-term interest rate.

Author: Xuezhong He
Publisher:
ISBN:
Category :
Languages : en
Pages : 54

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This paper analyzes the impact of dispersion and correlation in investors' beliefs on the cross-section of volatilities and correlations in stock returns. Theoretically, we show that, in a baseline model with logarithmic agents and constant beliefs, there is a positive relationship between belief dispersion and stock volatility, and a positive relationship between belief correlation and return correlation. Extensions to CRRA preference, learning, and multiple agents show that the baseline results are generally robust for reasonable model parameter values. Empirically, we find supporting evidence on the theoretical predictions of the baseline model using analysts' forecasts of earnings as a proxy for investors' beliefs, suggesting that disagreement provides a plausible explanation to the excess volatility and comovement in stock returns.

Author: Christian von Drathen
Publisher:
ISBN:
Category :
Languages : en
Pages : 50

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Book Description
Stock returns appear to comove in excess of common news about stock fundamentals. I examine comovement when stocks are added to or deleted from the FTSE 100 stock index, which are events without news about fundamantals. Using a natural experiment created by FTSE's index balancing rule, I find that random index turnover has no significant effect on comovement. Furthermore, non-random index turnover can introduce a selection bias that overstates the effect on comovement. Index turnover does not cause a change in comovement, but much rather it seems to be the reverse: a change in comovement can cause index turnover. My findings are consistent with the fundamentals-based hypothesis; rejections in the previous literature may be due to non-random index turnover.

Author: Robert J. Shiller
Publisher:
ISBN:
Category : Dividends
Languages : en
Pages : 40

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Simple efficient markets models imply that the covariance between prices of speculative assets cannot exceed the covariance between their respective fundamentals unless there is positive information pooling. Positive information pooling occurs when there is more information, in a sense defined here, about the aggregate of the fundamentals than there is about the individual fundamentals. With constant discount rates, the covariance between prices (detrended by dividing by a moving average of lagged dividends) in the U. K. and the U. S. exceeds the covariance of the measure of fundamentals, and there is no evidence of positive information pooling. Regression tests of forecast errors in one country on a real price variable in another country show significantly negative coefficients. When the present value formula uses short rates to discount, there is less evidence of excess comovement.