Financial time series exhibit a number of interesting properties that are difficult to explain with simple models. These properties include fat-tails in the distribution of price fluctuations (or returns) that are slowly removed at longer timescales, strong autocorrelations in absolute returns but zero autocorrelation in returns themselves, and multifractal scaling. Although the underlying cause of these features is unknown, there is growing evidence they originate in the behavior of volatility, i.e., in the behavior of the magnitude of price fluctuations. In this paper, we posit a feedback mechanism for volatility that closely reproduces the non-trivial properties of empirical prices. The model is parsimonious, contains only two parameters that are easily estimated, fits empirical data better than standard models, and can be grounded in a straightforward framework where volatility fluctuations are driven by the estimation error of an exogenous Poisson rate.
Correction to "Leverage and volatility feedback effects in high-frequency data" [J. Financial Econometrics 4 (2006) 353--384]
Bollerslev et al.（2006）研究了Heston（1993）随机波动率模型下平方收益率的互协方差。为了获得这些互协方差，作者使用了一个不正确的平方收益分布表达式。在这里，我们将获得平方收益率的正确分布，并检查在这个新分布下，Bollerslev et al.（2006）附录A.2中的结果仍然成立。
Institute of Data Science and NUS Graduate School for Integrative Sciences & Engineering, National University of Singapore（新加坡国立大学数据科学研究所及综合科学与工程研究生院）；Department of Mathematics and Risk Management Institute, National University of Singapore（新加坡国立大学数学系及风险管理研究所）
