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

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