Market turbulence did not begin with the fall of Lehman Brothers, and it will not end when the global economy recovers.1 Indeed, a variety of academic studies—using measures such as stock price volatility, the mortality of firms, the persistence of superior performance, the frequency of economic shocks, and the speed of technology dissemination—have concluded that volatility at the firm level increased somewhere between two- and fourfold from the 1970s to the 1990s (see sidebar, “Recommended reading”).