the source of most losses in the markets is people betting or gambling, as defined by the characteristics of their behavior, on a continuous-process risk activity.

All four primary sources of wealth creation represented in the Forbes 400 involve “idiosyncratic risk”—the kind of risk that, according to the tenets of modern portfolio theory, “rational” investors can and should eliminate by diversification. Yet most of the people on the list believed, and still believe, that focusing on what they know best is th