Performance Quality, Stock Returns and Idiosyncratic Volatility

The relation between firm's idiosyncratic volatility (IV) and stock returns has been explained by conflicting evidence, the contradiction has attracted the attention of many researchers. The impact of IV on stock return is depending on the stocks’ attributes. Tests have been performed using a panel data model with fixed effects, and the sample of 126 companies listed in Tehran Stock Exchange. The results show that in companies with high performance quality, the firm's IV are directly related to stock returns, and in companies with low performance quality, the firm's IV are inversely related to stock returns. The favorable quality increases the IV, and leads to positive returns, and The non-favorable quality increases the IV, and leads to negative returns. And there is a nonlinear,  shaped, relation between stock returns and IV. Increasing the level of IV to a certain level, initially, increases the firm's stock returns, but by increasing it more than before, cause a negative market reaction and a negative impact on stock returns.