This study investigates how uncertainty affects firms’ target capital structure using a panel data set of U.S. public manufacturers between 2003 and 2018 and finds that high-uncertainty firms have 10.1 (8.1) percentage points lower mean book (market) targets than low-uncertainty firms. This study also shows that the uncertainty effect on leverage targets is greater than the impact of firm size, market-to-book ratio, assets tangibility, R&D intensity, and industry median leverage, making uncertainty the most critical among all time-varying determinants of leverage targets. Further, this study finds that heightened uncertainty decreases debt tax shields, increases potential financial distress costs, and exacerbates debtholder–shareholder conflicts, thereby leading to a lower optimal or target leverage ratio.

We examine the effect of a large dividend tax cut on corporate investment efficiency by exploiting the 2003 personal taxation reform in the U.S. as a quasi-natural experiment. Using a difference-in-differences approach based on the probability that a firm’s marginal investor was an individual investor, we show that the 2003 dividend tax cut significantly improved the investment efficiency of U.S. listed firms. However, we find no evidence that the dividend tax cut increased the level of investment of U.S. listed firms. Further, we show that the tax cut increased investment efficiency by mitigating agency problems associated with the excessive free cash flows of overinvesting firms and by relaxing the financial constraints of underinvesting firms.

We study the joint effects of uncertainty and investment spikes on corporate leverage adjustments. In our baseline finding we show that, while uncertainty has a nontrivial adjustment speed effect for overlevered firms, underlevered firms are not greatly impacted. In our second baseline finding, we document asymmetric effects of investment spikes on the adjustment speed between overlevered and underlevered firms. Specifically, during the investment-spike period, underlevered firms adjust their leverage very promptly, whereas overlevered firms tend to adjust their leverage much more slowly. Bringing these two baseline analyses together in a combined analysis, conditional on the level of uncertainty, the investment regime has asymmetric effects between overlevered and underlevered firms. Specifically, when uncertainty is fixed, regardless of whether uncertainty is high or low, overlevered firms facing investment spikes tend to adjust their leverage slower than their non-spike counterparts, but underlevered firms facing investment spikes tend to adjust their leverage substantially faster than their non-spike counterparts. Further, we find that elevated uncertainty uniformly increases the speed of adjustment for overlevered firms without investment spikes, but the influence for underlevered firms without investment spikes is much less evident.