Theories in capital structure?

1. Trade-off theory: This theory suggests that companies must balance the benefits and costs of debt and equity financing. Debt financing offers tax advantages and can lower the cost of capital, but it also increases financial risk. Equity financing, on the other hand, does not require repayment and does not increase financial risk, but it can be more expensive due to the cost of issuing new shares.

2. Pecking order theory: This theory posits that companies prefer internal financing (retained earnings) over external financing (debt or equity) because external financing can signal that the company's stock is undervalued. When external financing is necessary, companies will first use debt, then equity, following a "pecking order" of financing sources.

3. Agency cost theory: This theory focuses on the conflicts of interest between shareholders and management. Managers may have incentives to take on excessive debt to increase their own compensation or to pursue risky projects that benefit them personally but harm shareholders. Shareholders may also have incentives to push for more debt to increase their own returns at the expense of bondholders.

4. Signaling theory: This theory suggests that a company's choice of capital structure can signal information to investors about the company's future prospects. For example, a company that issues equity may signal that it believes its stock is overvalued, while a company that issues debt may signal that it is confident in its ability to generate future cash flows.

5. Market timing theory: This theory suggests that companies may adjust their capital structure based on market conditions, such as interest rates or investor sentiment. Companies may issue debt when interest rates are low or equity when stock prices are high, in order to take advantage of favorable market conditions.

Traditional Theories:

- Net Income Approach (NI Approach): States that the weighted average cost of capital (WACC) will not change with different capital structures.
- Traditional Approach (Relevance Theory): Asserts that WACC is relevant for investment decisions and that the optimal capital structure is the one that minimizes WACC.

Modern Theories:

- Trade-off Theory: Suggests that the optimal capital structure involves a trade-off between:
- Tax benefits of debt
- Bankruptcy costs
- Pecking Order Theory: Firms prefer internal financing over external financing, and debt is used only when internal funds are insufficient.
- Agency Theory: Focuses on conflicts of interest between shareholders and debt holders, and argues that the optimal capital structure will balance these conflicts.
- Market Timing Theory: Firms adjust their capital structure based on perceived market conditions and the cost of capital.
- Signaling Theory: Management uses capital structure to signal firm-specific information to investors.

Contingency Theories:

- Industry-Specific Theory: Optimal capital structure varies across industries due to industry-specific factors, such as competitive forces and risk levels.
- Firm-Specific Theory: Optimal capital structure is unique to each firm and depends on factors such as firm size, profitability, and growth prospects.

Other Theories:

- Behavioral Approach: Considers the influence of psychological factors on capital structure decisions.
- Optimal Capital Structure in the Presence of Taxes: Tax laws can significantly impact the optimal capital structure.
- Capital Structure and Corporate Governance: Corporate governance mechanisms can influence the choice of capital structure.