Analyzing nearly 2,000 CEO turnovers in more than 1500 public U.S. firms between 1992 and 2006, Yihui Pan, Tracy Yue Wang, and Michael Weisbach find a strong relationship between CEO tenure and the firm’s stock return volatility. Volatility increases around the time of CEO turnover, and subsequently decreases. The researchers estimate that at the time of CEO turnover, uncertainty about management quality contributes to about 25 percent of the total stock return volatility.