Many recent empirical investment studies have found that the investment of financially constrained firms responds strongly to cash flow. Paralleling these findings is the disappointing performance of the q theory of investment: even though marginal q should summarize the effects of all factors...

We quantify how much nonfundamental movements in stock prices affect firm decisions. We estimate a dynamic investment model in which firms can finance with equity or cash (net of debt). Misvaluation affects equity values, and firms optimally issue and repurchase overvalued and undervalued...

We derive and test q-theory implications for cross-sectional stock returns. Under constant returns to scale, stock returns equal levered investment returns, which are tied directly to firm characteristics. When we use GMM to match average levered investment returns to average observed stock...