摘要：Abstract In this study, it is aimed to determine the effects of the borrowings on the structure of the capital of the companies whose stocks are traded in ISE-100. For this purpose, the financial statements of the companies traded in ISE-100 are obtained from the related web site and these data are analyzed with SPSS 17 software using the regression statistical model. At the end of the study, a low level functional relationship has been found out between Market-to-Book ratio and debt-to-capital ratio. The obtained results seem to be compatible with the generally accepted conclusion "the capital structures of the company are not affected by the debt exchange no matter what level of capital structure of the company is". As a result, the capital structures of the companies registered in the ISE-100 are not affected by debt-equity exchange as in the case of capital structure irrelevance principle. Thus, it can be stated that there is no optimal capital structure for a company and it is not required to search for such a capital structure. Key Words: Capital structure, leverage ratio, net operating income approach, pecking order theory.
