پيش بيني مخاطره پرتفوي بهينه در سهام شركتهاي پذيرفته شده بورس اوراق بهادار بدون توجه به روحيه سرمايه گذار

The Forecast of Optimum Portfolio Risk in Stocks of Firms in Security and Exchange Commission Regardless of Investment Spirit

Growth and development of economic of each country is depend on appropriate investing and planning. Always the existence of an objective scale for evaluating risk in financial decision making is useful. This scale must be independent from risk aversion (disaffection of anyone to risk), this research is consist of Targets. For achieving to target of this research, hypothesis were defined as: 1. With having a specific assurance %95 for example), risk can be estimated. 2. With having a specific assurance (%95 for example), numbers of necessary investments for achieving to amount of optimum risk tolerance can be found. Then inductive and deductive approaches have been used for acceptance or rejecting the hypothesis, population of this search are 429 companies that in 1378 to the end of 1383 which exist in security Exchange commission .That 50 of them have been selected between different industry by class sampling .The results of this research show that whit regression analysis we can estimate the rick of 50 stocks with regarding to market factors and move toward accepting first hypothesis. Finally , after done checks and test and errors, for testing second hypothesis the result that obtain is :We can achieve to composition of improved portfolio by forming of regression and defining improvement indexes (cut rate and ratio of additional return to beta), specially single — factor method for determining investment ratio in selected stocks as for limitation of amount of capital.