Extension Measure And Elusion Transform Of Stock Risk Under Uncertainty Profit Rate

Markowitz established the combination investment model on the thought of measuring t he r isk b y t he v ariance o f r evenves r ate a nd d eveloped t he t imes o f t he financial quantitative analysis. The model had important meaning at the theory and application. The limitation of measuring risk with variance are analyzed on base of Markowitz investment portfolio model . With the uncertainty of market fluctuate and economy, the different expect about profit rate and different endurance against risk, the stock investment has the uncertainty. Because of the uncertainty of expected profit rate and practical yield, it is difficult to accurately measure the profit rate. The paper discusses three core problems, i.e, a strict definition of risk, the mathematical description of risk and the risk measure index. In order to measure the risk of stock under uncertainty profit rate, this paper introduces the definition of extension interval numbers, several properties of extension interval numbers and linearity operation are given. Then, the new risk measure method is defined by applying the extension interval numbers. We set up the classical region matter-element and sectional region matter-element about expected profit rate in portfolio, calculate relation degree of practical yield about expected profit rate according to interval relation function.The definition can express the relation between risk rate and profit rate. It can reflect the investment action and the endurance ability against risk. Regarding to the dissatisfactory stock, this paper build the matter-element model of investment portfolio, design some index of stocks characters, fix the power quotiety of scale index, calculate satisfaction degree of stock and develop the method to transform investment portfolio.