| Abstract: | 
Forecasting volatility and quantiles of financial returns is essential for 
accurately measuring financial tail risks, such as value-at-risk and expected 
shortfall. The critical elements in these forecasts involve understanding the 
distribution of financial returns and accurately estimating volatility. This 
paper introduces an advancement to the traditional stochastic volatility 
model, termed the realized stochastic volatility model, which integrates 
realized volatility as a precise estimator of volatility. To capture the 
well-known characteristics of return distribution, namely skewness and heavy 
tails, we incorporate three types of skew-t distributions. Among these, two 
distributions include the skew-normal feature, offering enhanced flexibility 
in modeling the return distribution. We employ a Bayesian estimation approach 
using the Markov chain Monte Carlo method and apply it to major stock indices. 
Our empirical analysis, utilizing data from US and Japanese stock indices, 
indicates that the inclusion of both skewness and heavy tails in daily returns 
significantly improves the accuracy of volatility and quantile forecasts. |