We test the market timing theory of capital structure using an earnings-based valuation model that allows us to separate equity mispricing from growth options and time-varying adverse selection; thus avoiding the multiple interpretations of book-to-market ratio. We find that equity market mispricing plays a significant, if not dominant, role in the security choice decision. Our results are robust to the inclusion of proxies for time-varying growth options and alternate methods of measuring misvaluation.

We implement an earnings-based fundamental valuation model to test the impact of market timing on the firm's method of funding the financing deficit. We argue that our valuation metric provides a superior measure of equity misvaluation because it avoids multiple interpretation problems faced by the market-to-book ratio. It also eliminates the need to infer market timing based on the actions of corporate insiders or other indirect measures. We find a strong positive relation between the degree to which a firm is overvalued and the proportion of the firm's financing deficit that is funded with equity. This result is found cross-sectionally and through time and is robust to firm size, and other variables known to impact capital structure. We find evidence that overvaluation in the 1990s led to equity being increasingly preferred over debt. For a broad set of firms, market timing explains a significant portion of the variation in the type of security used to fund the financing deficit.

Decades of research confirm that, on average, stock split announcements generate positive abnormal returns. In our sample, 80% of CEO stock option grants are timed to occur on or before the split announcement date. With the average market-adjusted announcement return of 3.1%, awarding the grant before the split announcement results in an average gain per CEO-grant of 451,748. We find additional evidence consistent with timing of CEO stock trading around the split announcement. In the case of CEO stock sales, about two-thirds occur after the split announcement, resulting in an average gain of 345,613.

We find that equity mispricing impacts the speed at which firms adjust to their target leverage (TL) and does so in predictable ways depending on whether the firm is over- or underlevered. For example, firms that are above their TL and should therefore issue equity (or retire debt) adjust more rapidly toward their target when their equity is overvalued. However, when a firm is undervalued but needs to reduce leverage, the speed of adjustment is much slower. Our findings support the role of equity mispricing as an important factor that alters the cost of making capital structure adjustments.

Previous studies document a negative return to equity on the announcement of an SEO. However, the effects of SEO announcements on bonds have received little attention. We find that bondholders experience a significant positive return on the announcement of an SEO and this effect is more pronounced for bonds with lower ratings. We examine alternate explanations for bond market reactions to SEO announcements including the leverage risk reduction, wealth transfer, and information signaling hypotheses. Overall, our results are most consistent with the leverage risk reduction hypothesis.