We study the dynamic implications of capital investment in innovative capacity (IC) on future stock returns, investment, and profitability by modeling the unique effects of IC investment on uncertain option generation/exercise and postexercise revenue. The model highlights the diverse effects of IC investment on expected returns in different postinvestment regimes and yields the novel prediction that, under the neoclassical assumption of nonincreasing revenue returns, IC investment is positively related to subsequent cumulative stock returns with a lag. The model also predicts a positive effect of IC investment on future investment and profitability. We find strong empirical support for these predictions.