THE INVESTIGATION RELATIONSHIP BETWEEN VARIOUS MEASURES OF FIRM GROWTH AND SUSTAINABILITY OF THE CAPITAL STRUCTURE IN LISTED COMPANIES IN TEHRAN STOCK EXCHANGE

The purpose of this study was to evaluate the relationship between different measures of company's growth and sustainability of the capital structure. This study is a library and analysis scientific study based on an analysis of panel data. In this study, the financial data of 101 companies listed in Tehran Stock Exchange during the period 2006 to 2011 have been reviewed (606 companies -Year). To analyze the results of research, software Spss 20, Eviews7 and Minitab16 is used. The results of research in relation to first hypothesis of research indicate that there is a direct relationship between the company's growth opportunities and debt changes ratio. Furthermore, the results show that in relation to the second hypothesis confirmation, there is an inverse and significant relationship between profitability index and the ratio of debt changes ratio of companies. Also, according to the analysis made in relation to the third research hypothesis confirmation, we find that there is a direct and significant relationship between firm size and the debt changes ratio of companies. Also in connection with the fourth hypothesis of research, we find that there is an inverse and significant relationship between company's growth opportunities and changes ratio in retained earnings ratio of companies. Finally, results of research in connection with the fifth and sixth hypotheses confirmation suggest that is a direct and significant relationship between variables of profitability index and the factor of company's size with changes ratio in retained earnings of companies.

Growth opportunities, Profitability index ratio, Firm size, The ratio of debt changes, Ratio of changes in retained earnings