The document discusses various capital structure theories:
1. The net income approach suggests that changing the capital structure will change the cost of capital and value of the firm. It assumes no taxes and constant costs.
2. The net operating income approach assumes the overall cost of capital remains unchanged for different leverage levels. It focuses on how debt affects the risk and required return on equity.
3. The MM approach argues that the value and cost of capital are independent of capital structure under certain assumptions. Increased risk from debt is offset by lower cost of debt.
4. The traditional approach suggests moderate use of debt can lower costs up to a point, but costs rise sharply at very high leverage levels.