Volatility dynamics and heterogeneous markets

Recent research has suggested that intra-day volatility may possess a component structure, resulting either from the arrival of heterogeneous information or the actions of heterogeneous market agents. This paper reports direct evidence for the existence of such components in S&P500 index and DM/$ exchange rate data. Estimation of a FIGARCH model supports the contention that volatility dynamics result from multiple sources. Using a HARCH conditional variance model which defines volatility components over differing time horizons, confirmatory evidence of heterogeneous components is reported, in which context the impact of high-frequency speculation and noise-trading are particularly apparent. Copyright (c) 2006 John Wiley & Sons, Ltd.