It’s bad enough that battered banks relied on Gaussian VaR. Now corporates employ it.
It makes a wonderful (and possibly apocryphal) story. French mathematical wunderkind and father of fractal geometry Benoit Mandelbrot wandered into a colleague’s office in the early 1960s before giving a lecture on mathematical uncertainty, and there, on his friend’s chalk-board, was exactly the graph he planned to use. When queried, Mr. Mandelbrot’s friend said the chart tracked cotton prices back to 1880—one of the longest price data sets on record. When it, and other long-term time series, were sliced and diced into longer and shorter time-frames they consistently and clearly showed that asset prices are not characterized by the Gaussian, or normal, distribution. Mr. Mandelbrot published his findings in 1962.