Corporate Capital Structure: Equity vs Debt Financing Tradeoffs and Corporate Finance Decision Logic
Capital structure refers to the ratio in which a company uses equity and debt financing. This choice directly affects the weighted average cost of capital (WACC), financial flexibility, and shareholder returns. Different industries have distinct conventional capital structures — utilities typically use high debt (stable cash flows support debt service); high-tech startups typically use equity (unstable cash flows, risk-tolerant investors).
Modigliani-Miller and Real-World Corrections
The Modigliani-Miller theorem (1958, both authors are Nobel laureates) proves under perfect market assumptions that enterprise value is independent of capital structure. This doesn’t hold in practice precisely because the assumptions don’t hold: taxes (interest payments are tax-deductible, dividends are not), financial distress costs (excessive debt increases bankruptcy risk), and information asymmetry (information gap between management and external investors affects financing choices).
Tax Shield: interest paid to creditors is deductible before tax. At a 25% corporate tax rate, ¥1M in interest payments reduces tax by ¥250,000 — a government implicit subsidy on debt financing.
Trade-off Theory: optimal capital structure balances tax shield benefits against financial distress costs. Apple, despite holding hundreds of billions in cash, still issues bonds — partly to capture the tax shield while avoiding repatriating overseas cash at high US tax rates (historical context, partially changed).
