The objective of this research is to test the stability of systematic risk coefficients of stocks listed on the Damascus Securities Exchange through the period (4/1/2010 – 28/10/2013), and therefore the ability to use the values of these coefficients
to calculate the required rate of return on investment in the individual stocks and portfolios.
The data related to the closed prices of stocks and market index were collected from the website of DSE, which is used to estimate the values of systematic risk (Beta). Then the researcher has tested the stability of the coefficients throughout the entire period and the three sub-periods each one consists of five yearly quarters by using the time as a variable in the regression model, and by testing the significance of the coefficient of time variable.
The results of the research show that greater than 80% of these coefficients were insignificant, that is, the higher percentage of stocks have a stable Beta, and can be used to calculate the required rate of return on investment, therefore suitable investment decisions may be made upon these results.
