Need for new market theories: Mandelbrot

Pt 2: In a rare in-depth interview recorded last year the mathematician Benoit Mandelbrot, who died last week, says nothing stops big price changes (for instance, a company becoming instantly worthless) and that now is the time to start again with theories of markets. Benoit Mandelbrot was an emeritus professor of mathematics at Yale University and he was speaking to John Authers, Lex editor.