This document provides an overview of capital structure concepts and theories. It defines capital structure as the mix of owned and borrowed capital used to finance a company's assets. The key points are: - Capital structure theories include the net income, net operating income, Modigliani-Miller, and traditional approaches. - Forms of capital structure include equity shares, preference shares, debentures/bonds, and long-term loans. - The net income approach states that increasing debt lowers cost of capital until risks increase costs. The net operating income approach argues risks always increase costs, making structure irrelevant. - Modigliani-Miller's theory depends on whether taxes exist, finding