The article is devoted to the study of the problems of forming the capital structure of a corporation. Static, dynamic, behavioral theories of capital structure are considered through the prism of their evolutionary development: traditional theory; basic and modified Modigliani-Miller theories; compromise theory; agency cost theory; signaling theory; theory of hierarchy of funding sources; monitoring cost theory; theory of information cascades; market tracking theory; theory of the influence of personal qualities of top management on the capital structure of a corporation. As a result of the study of the theoretical basis, the main factors determining the capital structure of the corporation were identified. The conclusion is formulated that the presence of different theoretical approaches, the uniqueness of the financial and economic state, the ambiguity of the development dynamics of each specific corporation determine the advisability of using the decision tree methodology in the development and justification of management initiatives in terms of the formation of the optimal capital structure of the corporation. Within the framework of this methodology, it is advisable to consider and evaluate the effectiveness of possible solutions based on a synthesis of several theoretical approaches depending on the current internal and external business environment.