Just finished reading Benoit Mandelbrot’s utterly essential The Misbehavior of Markets again (i.e., this, like Reminiscences, has become a perpetual read for me), therefore, a flurry of quotes are likely to come your way over the next few days.

Here’s today’s:   emphasis mine…

“Reality: Patently, people are not alike—even if differences in wealth are disregarded. Some buy and hold stocks for twenty years, for a pension fund; others flip stocks daily, speculating on the Internet. Some are “value” investors who look for stocks in good companies temporarily out of fashion; others are “growth” investors who try to catch a ride on rising rockets. Once you drop the assumption of homogeneity, new and complicated things happen in your mathematical models of the market. For instance, assume just two types of investors, instead of one: fundamentalists who believe that each stock or currency has its own, intrinsic value and will eventually sell for that value, and chartists who ignore the fundamentals and only watch the price trends so they can jump on and off bandwagons. In computer simulations by economists Paul De Grauwe and Marianna Grimaldi at the Catholic University of Leuven, in Belgium, the two groups start interacting in unexpected ways, and price bubbles and crashes arise, spontaneously. The market switches from a well-behaved “linear” system in which one factor adds predictably to the next, to a chaotic “non-linear” system in which factors interact and yield the unanticipated. And that is with just two classes of investors. How much more complicated and volatile is the real market, with almost as many classes as individuals?”