Aggregate idiosyncratic volatility spiked nearly fivefold during the Internet boom of the late 1990s, dwarfing in magnitude a moderately increasing trend. While some researchers argue that this rise in idiosyncratic risk was the result of changes in the characteristics of public firms, others argue that it was driven by the changing sentiment of irrational traders. We present evidence that the marketwide decline in maturity of the typical public firm can explain most of the increase in firm-specific risk during the Internet boom. Controlling for firm maturity, we find no evidence that investor sentiment drives idiosyncratic risk throughout the Internet boom.

We show that stock market liquidity is an important determinant of the cost of raising external capital. Using a large sample of seasoned equity offerings, we find that, ceteris paribus, investment banks' fees are significantly lower for firms with more liquid stock. We estimate that the difference in the investment banking fee for firms in the most liquid vs. the least liquid quintile is about 101 basis points or 21% of the average investment banking fee in our sample. Our findings suggest that firms can reduce the cost of raising capital by improving the market liquidity of their stock.

Recent studies document both a significant decline in firms’ propensity to pay dividends and a significant increase in firms’ propensity to repurchase shares and issue equity over the past 30 years. In this paper we test whether firms’ net cash disbursements to equity holders have declined in a pattern similar to firms’ propensity to pay dividends. Contrary to the evidence using dividends, we find no evidence that the conditional propensity to distribute net cash to equity holders has declined over the past 3 decades. Surprisingly, we find that, conditional on firm characteristics, net payout yields have been increasing over time.

Stocks that hedge sustained market downturns should have low expected returns, but they do not. We use ex ante firm characteristics and covariances to construct a tradable safe minus risky (SMR) portfolio that hedges market downturns out of sample. Although downturns (peaks to troughs in market index levels at the business-cycle frequency) predict significant declines in gross domestic product growth, SMR has significant positive average returns and 4-factor alphas (both around 0.8% per month). Risk-based models do not explain SMR’s returns, but mispricing does. Risky stocks are overpriced when sentiment is high, resulting in subsequent returns of -0.9% per month.