investigating the relationship between ownership structure and debt cost with an emphasis on the role of financial crisis

Capital structure discusses the composition of company financing sources including shortterm debts, bonds, longterm debt, preferred stock, and common stock. some firms define no predetermined plan for capital structure; rather, the capital structure is determined respecting to financial decisions taken by financial management lacking any specific plan. despite these firms may succeed in shortterm, finally they face major problems for required financing activities.  the main objective of the present research is to study the relationship between ownership structure and debt cost focusing on the role of financial crisis in companies listed in tehran stock exchange within 20112015 (a fiveyear period). the results show that there is no significant relationship between the type of ownership and debt cost; in addition, financial crisis may not mediate the relationship between ownership and debt cost.  on the other hand, the results also indicate that there is no significant relationship between the proportion of institutional owners and debt cost; further, financial crisis shows no mediating role.