a comprehensive trend of capital structure case study of companies listed in tse

capital structure puzzle is a challenging issue in corporate finance. different researchers attempt to identify ways to determine optimized capital structure which minimizes firm’s cost of capital and maximizes its value, by proposing variety of theories. in line with forming new theories and introducing determinant variables, the absence of comprehensive research which simultaneously tests existing theories is obvious. considering the issue literature perfectly, we attempt to identify introduced determinant variables and propose appropriate model using forward stepwise data reduction algorithm and econometrics tools. to achieve this objective, we select 78 companies listed in tehran stock exchange and consider the effects of trade-off theory, pecking order theory and market timing theory from 1380 to 1384. finally we propose a regression model which is the best estimation of existing data for the whole instance and each cluster of industry.