Chapter 17: Optimal Debt Levels & Capital Structure

Optimal Debt Levels & Capital Structure begins by reintegrating corporate taxes into the financing decision, explaining how interest payments create a valuable tax shield that effectively lowers the firm's tax bill and increases the after-tax value of the firm. This benefit, however, is nuanced by personal taxes on interest and equity income, which can reduce or neutralize the corporate tax advantage depending on the tax environment. The discussion then shifts to the costs of financial distress, distinguishing between direct bankruptcy costs, such as legal and administrative fees, and the often more damaging indirect costs, including lost customers, supplier diffidence, and operational inefficiencies that occur even without formal default. A significant portion of the chapter is dedicated to agency costs and the conflicts of interest between shareholders and bondholders during distress, illustrating how levered firms may engage in value-destroying "games" like risk-shifting (gambling with creditors' money), refusing to contribute equity to positive net present value projects (debt overhang), or bait-and-switch tactics with debt seniority. These concepts culminate in the trade-off theory of capital structure, which posits that firms balance the marginal benefits of tax shields against the marginal present value of financial distress costs. The chapter contrasts this with the pecking order theory, which argues that asymmetric information—where managers know more than investors—drives financing choices. Under the pecking order, firms prefer internal funds first to avoid the negative signaling associated with issuing equity, resorting to debt second, and issuing new equity only as a last resort. Finally, the text explores the concept of financial slack, highlighting the value of having ready cash for future investment opportunities versus the potential dark side of free cash flow, where excess liquidity might encourage management to overinvest or waste resources. The chapter concludes by reviewing empirical evidence, noting that while the trade-off theory explains industry differences based on asset tangibility, the pecking order better explains why the most profitable firms often borrow the least.