A multi-time scale non-Gaussian model of stock returns
Abstract
Description
We propose a stochastic process for stock movements that, with just one source of Brownian noise, has an instantaneous volatility that rises from a type of statistical feedback across many time scales. This results in a stationary non-Gaussian process which captures many features observed in time series of real stock returns. These include volatility clustering, a kurtosis which decreases slowly over time together with a close to log-normal distribution of instantaneous volatility. We calculate the rate of decay of volatility-volatility correlations, which depends on the strength of the memory in the system and fits well to empirical observations.
Comment added pertaining to volatility autocorrelation, clarifying approximation used in calculation
Comment added pertaining to volatility autocorrelation, clarifying approximation used in calculation