Benoit Mandelbrot

fractals; fat-tailed finance.

Benoit Mandelbrot (1924–2010) spent most of his career as an IBM Fellow and later as a professor at Yale. He developed fractal geometry—the mathematics of self-similar, irregular shapes found in nature—and introduced the Mandelbrot set. He applied these ideas to financial markets in works such as 'The (Mis)behaviour of Markets', arguing that standard models dangerously underestimate risk.