Dispersion and Volatility in Stock Returns


Book Description

This paper studies three different measures of monthly stock market volatility: the time-series volatility of daily market returns within the month; the cross-sectional volatility or 'dispersion' of daily returns on industry portfolios, relative to the market, within the month; and the dispersion of daily returns on individual firms, relative to their industries, within the month. Over the period 1962-97 there has been a noticeable increase in firm-level volatility relative to market volatility. All the volatility measures move together in a countercyclical fashion. While market volatility tends to lead the other volatility series, industry-level volatility is a particularly important leading indicator for the business cycle.




Volatility and Correlation


Book Description

In Volatility and Correlation 2nd edition: The Perfect Hedger and the Fox, Rebonato looks at derivatives pricing from the angle of volatility and correlation. With both practical and theoretical applications, this is a thorough update of the highly successful Volatility & Correlation – with over 80% new or fully reworked material and is a must have both for practitioners and for students. The new and updated material includes a critical examination of the ‘perfect-replication’ approach to derivatives pricing, with special attention given to exotic options; a thorough analysis of the role of quadratic variation in derivatives pricing and hedging; a discussion of the informational efficiency of markets in commonly-used calibration and hedging practices. Treatment of new models including Variance Gamma, displaced diffusion, stochastic volatility for interest-rate smiles and equity/FX options. The book is split into four parts. Part I deals with a Black world without smiles, sets out the author’s ‘philosophical’ approach and covers deterministic volatility. Part II looks at smiles in equity and FX worlds. It begins with a review of relevant empirical information about smiles, and provides coverage of local-stochastic-volatility, general-stochastic-volatility, jump-diffusion and Variance-Gamma processes. Part II concludes with an important chapter that discusses if and to what extent one can dispense with an explicit specification of a model, and can directly prescribe the dynamics of the smile surface. Part III focusses on interest rates when the volatility is deterministic. Part IV extends this setting in order to account for smiles in a financially motivated and computationally tractable manner. In this final part the author deals with CEV processes, with diffusive stochastic volatility and with Markov-chain processes. Praise for the First Edition: “In this book, Dr Rebonato brings his penetrating eye to bear on option pricing and hedging.... The book is a must-read for those who already know the basics of options and are looking for an edge in applying the more sophisticated approaches that have recently been developed.” —Professor Ian Cooper, London Business School “Volatility and correlation are at the very core of all option pricing and hedging. In this book, Riccardo Rebonato presents the subject in his characteristically elegant and simple fashion...A rare combination of intellectual insight and practical common sense.” —Anthony Neuberger, London Business School




Idiosyncratic Return Volatility in the Cross-section of Stocks


Book Description

This paper uncovers the changes in the cross-sectional distribution of idiosyncratic volatility of stocks over the period 1963--2008. The contribution of the top decile to the total market idiosyncratic volatility increased, while the contribution of the bottom decile decreased. We introduce a simple theoretical model showing that larger capital of Long/Short-Equity funds further exacerbates large idiosyncratic shocks but attenuates small idiosyncratic shocks. This effect is stronger for more illiquid stocks. Time-series and cross-sectional results are consistent with the predictions of the model. The results are robust to industry affiliation, stock liquidity, firm size, firm leverage, as well as sign of price change. These findings highlight the roll of hedge funds and other institutional investors in explaining the dynamics of extreme realizations in the cross-section of returns.










The Cross-Sectional Dispersion of Stock Returns, Alpha and the Information Ratio


Book Description

Both the cross-sectional dispersion of U.S. stock returns and the VIX provide forecasts of alpha dispersion across high- and low-performing portfolios of stocks that are statistically and economically significant. These findings suggest that absolute return investors can use cross-sectional dispersion and time-series volatility as signals to improve the tactical timing of their alpha-focused strategies. Because active risk increases by a greater amount than alpha, however, high return dispersion/high VIX periods are followed by slightly lower information ratio dispersion. Therefore, relative return investors who keep score in an information ratio framework are unlikely to find return dispersion useful as a signal regarding when to increase or decrease the activeness of their portfolio strategies.




Cross-Sectional Return Dispersion and the Equity Premium


Book Description

In this paper, I examine whether stock return dispersion (RD) provides useful information about future stock returns. RD consistently forecasts a decline in the excess market return at multiple horizons, and compares favorably with alternative predictors used in the literature. The out-of-sample performance of RD tends to beat the alternative predictors, and is economically significant as indicated by the certainty equivalent gain associated with a trading investment strategy. RD has greater forecasting power for big and growth stocks compared to small and value stocks, respectively. I discuss a theoretical mechanism giving rise to the negative correlation between RD and the equity premium.