We test how market overvaluation affects corporate innovation. Estimated stock overvaluation is strongly associated with measures of innovative inventiveness (novelty, originality, and scope), as well as research and development (R&D) and innovative output (patent and citation counts). Misvaluation affects R&D more via a nonequity channel than via equity issuance. The sensitivity of innovative inventiveness to misvaluation increases with share turnover and overvaluation. The frequency of exceptionally high innovative inputs/outputs increases with overvaluation. This evidence suggests that market overvaluation may generate social value by increasing innovative output and encouraging firms to engage in “moon shots.”

This paper uses pre‐offer market valuations to evaluate the misvaluation and Q theories of takeovers. Bidder and target valuations (price‐to‐book, or price‐to‐residual‐income‐model‐value) are related to means of payment, mode of acquisition, premia, target hostility, offer success, and bidder and target announcement‐period returns. The evidence is broadly consistent with both hypotheses. The evidence for the Q hypothesis is stronger in the pre‐1990 period than in the 1990–2000 period, whereas the evidence for the misvaluation hypothesis is stronger in the 1990–2000 period than in the pre‐1990 period.