EFF/KRF: Any current situation is always somewhat unprecedented and somewhat old stuff. Large declines in stock prices occur several times during the last 80 years. The nearby plot of the volatility of daily market returns shows that the current high volatility also has precedents in 1987 and in the 1930s, and to a lesser extent in 2000-2002. Periods of business uncertainty (for example, the onset of a recession) are typically associated with stock price declines and increases in volatility.
Eugene Fama and Ken French are members of the Board of Directors of the general partner of, and provide consulting services to Dimensional Fund Advisors LP.