統計学輪講(第17回) 日時 2017年10月10日(火) 14時55分~16時35分 場所 経済学部新棟3階第3教室 講演者 大森 裕浩 (経済) 演題 Realized Stochastic Volatility Models with Skewed t Distribution 概要 The predictive performance of the realized stochastic volatility model which incorporates the asymmetric stochastic volatility model with the realized volatility, is investigated. Considering well known characteristics of financial returns, heavy tail and negative skewness, the model is extended by employing wider class distributions including the generalized hyperbolic skew Student's t-distribution, for financial returns. With the Bayesian estimation scheme via Markov chain Monte Carlo method, the model enables us to estimate the parameters in the return distribution and in the model jointly. It also makes it possible to forecast volatility and return quantiles by sampling from their posterior distributions jointly. The model is applied to quantile forecasts of financial returns such as value-at-risk and expected shortfall as well as volatility forecasts and those forecasts are evaluated by various tests and performance measures. Empirical results with the US and Japanese stock indices, Dow Jones Industrial Average and Nikkei 225, show that the extended model improves the volatility and quantile forecasts especially in some volatile periods. This is a joint work with Makoto Takahashi and Toshiaki Watanabe.