利用传统的均值.方差模型研究了具有最低投资比例约束时的证券投资组合问题,首先得到了模型的前沿边界及有效边界存在的充要条件及其本质特征,然后根据这些结论给出了确定其前沿边界及有效边界解析表达式的具体方法和步骤.该方法是一种解析分析法,计算量比较小且几乎无误差,可以准确且快速的确定最低投资比例约束下证券组合有效边界的解析式.最后作为结论的直接应用和说明,利用中国股票市场数据给出了一个实例分析.
This paper explores the mean-variance model to study the portfolio selection problem with minimum investment proportion constraint. First we obtain existence conditions and features of the efficient frontier and boundary of mean-variance model, then we propose a specific solution method and procedure to obtain the explicit expression of efficient frontier and boundary of the model. Finally, as an application and a demonstration of our results, we present a numerical example using the real data of Chinese stock market.