Test of Fama and French Three-Factor Model Components Effects on Portfolio Return Variance

The purpose of this study is to test the Fama and French three-factor model in Tehran Stock Exchange. In order to do this, six portfolios including 616 stocks were formed for the years 2004-2009, regarding the size and the book values to the market value ratio. The results indicated that the beta, the size and the book value to market value ratio had significant effects on portfolio return. Adding two factors of the size of the company and the book value to market value ratio to the single factor CAMP resulted in increase in the coefficient of determination. This implies that the three-factor model describes variance variability of the percentage of portfolio return more than CAMP. Two factors of the size and the book value to market value ratio describe variance variability of the portfolio return considerably and their coefficients are statistically significant