在不做任何分布假设的条件下,利用非参数核估计方法对风险度量条件风险价值(conditional value-at-risk, CVaR)进行估计,得到CVaR的两步核估计公式.然后用估计出来的CVaR代替理论上的CVaR建立均值.CVaR模型,实现对风险估计与投资组合优化同时进行,并基于迭代思想设计求解该模型的简单算法.蒙特卡洛模拟结果表明基于两步核估计方法的投资组合优化模型和算法比现有的方法更加有效,估计出来的组合边界误差更小.引入无风险资产后,文中的模型和算法同样适用.最后,为说明其应用价值,采用中国A股市场的日收益率数据进行了实例分析.
The paper first applies nonparametric kernel estimation method to estimating CVaR which is currently a popular risk measurement tool, then derives a two-step kernel estimator of CVaR with distribution-free specification. Next, a two-step kernel estimator of CVaR is embed into the mean-CVaR portfolio optimization models to derive financial risk estimation and portfolio optimization at the same time. A simple iterative algorithm is designed to solve these models. Monte Carlo simulation result shows that the portfolio optimization models and the algorithm based on the two-step kernel estimator of CVaR is feasible and effective, and that the estimated error of portfolio frontier is very small. The models and algorithm above apply to a risk-free security. Finally, an empirical analysis of daily return data from Chinese A-stock market is presented to illustrate the application of this research.