Financing decisions for investment are one of the important tasks of the company in determining
the best composition. On the other hand, how to finance the company’s assets for individuals
and institutions is important, and how much debt and stocks the company has used to finance its
assets, is important because it depends on the company’s financing decisions will be affected. This
study investigates the application of nonlinear mathematical modeling in panel data analyses of the
pecking order theory in capital structure using multiple regression in the Tehran stock exchange.
The research period is from 2014 to 2019. In this research, panel data regression has been used to
test the hypotheses. To collect information and data, the library method, and to test the research
hypotheses, panel data and panel analysis using multiple regression have been used. The main
hypothesis of this research is based on the fact that in order to Management decisions about the
optimal capital structure of the company can be based on the theory model of the pecking order.
In the results of this study, it seems that the companies in question to finance themselves, in fact,
follow the mathematical model used in the theory of pecking order.