Parrino, Robert, and Michael S. Weisbach, 1999, “Measuring investment distortions arising from stockholder-bondholder conflicts,” *The Journal of Financial Economics 53*, 3-42.

**Purpose:** This paper calculates the expected wealth transfer between stock- and bondholders occurring when a firm begins a new project. It also estimates how stockholder-bondholder conflict impacts investment decisions, and whether it can explain cross-sectional variation in capital structure.

**Findings:**

- There will be underinvestment when the firm is faced with safe projects.
- Stockholders demand a higher return than the CAPM rate.
- This effect is stronger for high-leverage firms.

- Safe projects with low returns benefit bondholders at the expense of equity holders.

- There will be overinvestment when the firm is faced with risky projects.
- Stockholders are willing to gamble, and will even invest in negative NPV projects if the potential payoff is high.
- This effect is also stronger for high-leverage firms.

- Risky projects with negative expected (but high potential) payoffs benefit equity holders at the expense of bondholders.

- Longer debt duration is vulnerable to larger agency problems
- Lower marginal tax rates lead to slightly larger distortions
- The stockholder-bondholder conflict does exist and there do seem to be empirical investment distortions, but these distortions are too small to be useful in explaining most firms’ capital structure decisions.
- The distortion is only 0.14% for a firm with 20% debt-to-capital ratio, compared with a 3% noise factor in measuring cost of capital

**Motivation:** Managers seek to maximize shareholder value, not necessarily firm value. The “underinvestment problem” is when managers avoid a positive NPV project that would increase firm value but would lower stockholder value. The “overinvestment problem” is when managers undertake a negative NPV project that lowers firm value but raises stockholder value. These agency problems have been widely discussed in the literature for decades, but there is no consensus on their magnitude or on how important they really are.

**Data/Methods:** Use numerical simulations to estimate the impact of debt on the investment decisions of a levered firm whose managers seek only to maximize stockholder value. Compute the stockholder-bondholder wealth transfer accompanying projects with known characteristics.

- Compustat data for firms from 1981-1995
- Monte Carlo: Assume a firm with known cash flows following a random walk without drift for 30 years, after which cash flows are static. Assume a project financed entirely with equity, whose cash flows similarly follow a random walk without drift for 30 years. Assume a correlation of 0.5 between firm and project cash flows, run the simulation 5,000 times, and compute the ex ante value of debt and equity each time.
- Value of debt is the sum of discounted future cash flows to bondholders.
- Value of equity is the discounted cash flows to stockholders plus a terminal value.

**Conclusions: **Distortions in stockholder-bondholder required investment returns vary along several dimensions. However, for the typical firm they are much smaller than the noise in cost-of-capital measurement. The effect exists but is too small to explain cross-sectional variation in capital structure.