Investigating the Effect of Concentrated Ownership in Family and Non-Family Firms on Performance of Companies Listed in Tehran Stock Exchange

The purpose of this research is to examine the effect of ownership concentration in non-family firms and family firms (both with a family and nonfamily CEO) and also the impact of family ownership on the firm performance. The research sample includes 125 companies Listed in Tehran Stock Exchange in the period of 2008-2016 and the regression models are estimated using panel data. The results showed that ownership concentration have no effect on performance (both of return on assets and Tobin-q) in family firms (with family and nonfamily CEO) and non-family firms. The other research result indicates family firms with family CEO and family firms with non-family CEO has not any significant effect on performance.