Measuring chance and skill of the manager s performance assessment in the investment companies

This study has examined the net yield surplus earned by the investment companies Managers, and using the net yield surplus the chance and skill were also examined.The measurement criterion for net sur plus was Jensen’s Alpha and research data for 25 bourse bonds investment companies of Tehran were extracted during 36 months periods. After the approval of net yield surplus earned by these companies they were devided into three categories based on Jensen’s Alpha (a 0) and finally chance was measured in the investment companies. The results showed thatin 10 percent level of confidence it is expected that 22 percent of investment companies were considered skillful,but only 19 percent of them were skillful and 3 percent of them were by chance. Similarly, in 10 percent level of confidence the investment companies were without skill, but exactly 7 percent were without skill, the rest of them were by chance.