When Does the Market Matter? Stock Prices and the Investment of Equity-Dependent Firms
用一个简单模型说明，当企业依赖外部股权融资时，其投资对股票价格的非基本面波动更敏感。实证发现，股权依赖程度高的企业（KZ指数前五分之一）的投资对股价的敏感度是低依赖企业的近三倍。
We use a simple model to outline the conditions under which corporate investment is sensitive to nonfundamental movements in stock prices. The key prediction is that stock prices have a stronger impact on the investment of "equity-dependent" firms—firms that need external equity to finance marginal investments. Using an index of equity dependence based on the work of Kaplan and Zingales, we find support for this hypothesis. In particular, firms that rank in the top quintile of the KZ index have investment that is almost three times as sensitive to stock prices as firms in the bottom quintile.