The concept of debt overhang (that is, an equity-maximizing levered firm will under-invest relative to a firm-value-maximizing firm) is well established in the literature. A number of papers have demonstrated it as delayed investment (when investment size is specified) or smaller investment (when investment time is specified). However, there is no work on the underinvestment effect when the firm chooses both size and timing of investment, as it usually does in real life. This is what our paper focuses on. When the firm has the flexibility to choose both size and time, the effect is complicated by the fact that delayed investment results in larger investment, which suggests that the underinvestment problem might be mitigated. We find, however, that the effect depends on how underinvestment is measured. When measured by the expected present value of investment, flexibility can mitigate or exacerbate the underinvestment problem, depending on the cost of installing capacity. But when measured by the agency cost, flexibility always exacerbates the underinvestment problem. It is shown numerically that, at the optimal leverage ratio, the agency cost with plausible parameter values can be economically significant. Thus, with the flexibility of choosing both time and size of investment, the debt overhang problem can be of significant practical relevance in corporate investment decisions. K E Y W O R D S agency cost, contingent-claim model, debt overhang, investment flexibility, investment trigger, underinvestment
INTRODUCTIONThis paper studies the debt overhang (or underinvestment) problem and the associated agency cost when a firm has the flexibility to choose both the timing and the size of its investment. Although there is a sizeable literature on debt overhang and its effect on corporate investment, the existing papers examine a firm's investment decision when it chooses either the investment timing (for given size) or the investment size (for given timing); examples are Chen and /journal/jbfa J Bus Fin Acc. 2019;46:784-809.
LITERATUREAs mentioned above, a number of studies analyze the debt overhang problem when the investment size is specified and the firm chooses investment timing optimally. These studies show that the second-best investment trigger exceeds the first-best trigger, implying delayed investment or underinvestment. Mauer and Ott (2000) and Mello and Parsons (1992) demonstrate underinvestment but report very small agency costs. Pawlina (2010) also finds extremely small agency cost (except for the unusual scenario of negative growth), and shows that debt renegotiation in financial 1 It has been shown that firms that invest later choose a larger size or capacity, thus it is important to study the capacity decision next to the timing decision (