Asymmetric Volatility and Risk in Equity Markets
Asymmetric Volatility and Risk in Equity Markets

Author: Geert Bekaert

Publisher:

Published: 1997

Total Pages: 72

ISBN-13:

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It appears that volatility in equity markets is asymmetric: returns and conditional volatility are negatively correlated. We provide a unified framework to simultaneously investigate asymmetric volatility at the firm and the market level and to examine two potential explanations of the asymmetry: leverage effects and time-varying risk premiums. Our empirical application uses the market portfolio and portfolios with different leverage constructed from Nikkei 225 stocks, extending the empirical evidence on asymmetry to Japanese stocks. Although volatility asymmetry is present and significant at the market and the portfolio levels, its source differs across portfolios. We find that it is important to include leverage ratios in the volatility dynamics but that their economic effects are mostly dwarfed by the volatility feedback mechanism. Volatility feedback is enhanced by a phenomenon that we term covariance asymmetry: conditional covariances with the market increase only significantly following negative market news. We do not find significant asymmetries in conditional betas.

Volatility Clustering, Asymmetry and Hysteresis in Stock Returns
Volatility Clustering, Asymmetry and Hysteresis in Stock Returns

Author: Michel Crouhy

Publisher:

Published: 1998

Total Pages:

ISBN-13:

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Encompassing a very broad family of ARCH-GARCH models we show that heteroskedasticity, already well documented for the US market, is a worldwide phenomenon. The AT-GARCH (1,1) model, where volatility rises more in response to bad news than to good news, and where news is considered bad only below a certain level, is found to be a remarkably robust representation of worldwide stock market returns. The residual structure is then captured by extending ATGARCH (1,1) to an hysteresis model, HGARCH, where we model structured memory effects from past innovations. Obviously, this feature relates to the psychology of the markets and the way traders process information. For the French stock market we show that a shock of either sign may affect volatility differently, depending on the recent past being characterized by either all positive or all negative returns. In the same way a longer term trend of either sign may also influence the impact on volatility of current innovations. It is found that bad news is discounted very quickly in volatility, this effect is reinforced when it comes after a negative trend in the stock index. On the opposite, good news has a very small impact on volatility except when it is clustered over a few days, which in this case reduces volatility substantially.

Asymmetric Effects of Return and Volatility on Correlation between International Equity Markets
Asymmetric Effects of Return and Volatility on Correlation between International Equity Markets

Author: Abderrahim Taamouti

Publisher:

Published: 2009

Total Pages: 49

ISBN-13:

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How the correlation between equity returns behaves during market turmoils has been an issue of discussion in the international finance literature. Some research suggest an increase of correlation during volatile periods [Ang and Bekaert, 2002], while others argue its stability [Forbes and Rigobon, 2002]. In this paper, we study the impact of returns and volatility on correlation between international equity markets. Our objective is to determine if there is any asymmetry in correlation and identify the main explanation for this asymmetry. Within a framework of autoregressive models we quantify the relationship between return, volatility, and correlation using the generalized impulse response function and we test for the asymmetries in the return-correlation and volatility-correlation relationships. We also examine the implications of these asymmetric effects for the optimal international portfolio. Empirical evidence using weekly data on US, Canada, UK, and France equity indices, show that without taking into account the effect of return, there is an asymmetric impact of volatility on correlation. The volatility seems to have more impact on correlation during market upturn periods than during downturn periods. However, once we introduce the effect of return, the asymmetric impact of volatility on correlation disappears. These observations suggest that, the relation between volatility and correlation is an association rather than a causality. The strong increase in the correlation is driven by the market direction and the level of return rather than the level of the volatility. These results are confirmed using some tests of the asymmetry in volatility-correlation and return-correlation relationships in separate models and then in a joint model. Finally, we find that taking into account the asymmetric effect of return on correlation leads to an average financial gain ranged between 3.35 and 37.25 basis points for optimal international diversification.

Stock Market Volatility
Stock Market Volatility

Author: Greg N. Gregoriou

Publisher: CRC Press

Published: 2009-04-08

Total Pages: 654

ISBN-13: 1420099558

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Up-to-Date Research Sheds New Light on This Area Taking into account the ongoing worldwide financial crisis, Stock Market Volatility provides insight to better understand volatility in various stock markets. This timely volume is one of the first to draw on a range of international authorities who offer their expertise on market volatility in devel

Volatility and Correlation
Volatility and Correlation

Author: Riccardo Rebonato

Publisher: John Wiley & Sons

Published: 2005-07-08

Total Pages: 864

ISBN-13: 0470091401

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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