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The most important take-away from Mandelbrot / fractals as it applies to finance should be the realization that fractals can represent better ways of presenting
by sabj 16y ago
The most important take-away from Mandelbrot / fractals as it applies to finance should be the realization that fractals can represent better ways of presenting or simulating financial data than brownian motion / random walks / Black-Scholes. As to why this hasn't been accepted more broadly - well, as the article briefly mentions, there are powerful individual incentives for people to continue to play along in the charade.
If this has not been proved EXTREMELY WELL by events in recent history, I don't know when it would be - but whether from LTCM, or more recently seeing so many CDS etc blow up, it is obvious that many "once in a million" probability events exist than are considered in a proper normal distribution.
Mandelbrot was once asked whether he had any particularly successful strategies for dealing with the market. He said, well, I don't discuss those things - because if I was correct, everyone would follow my lead, and the strategies would no longer work; and if I was wrong, people would discredit the thinking behind it!
- some-dude 16y agoModels with constant-volatility random walks aren't favoured over "fractal" models because of some elaborate charade or flawed incentives. They are used because they are tractable models that can be used to make predictions. Fractal models are not. Financial models are just like any other engineering tools. They approximate reality so they can be useful; but violate their assumptions or use them outside of their intended purpose, and they're likely to blow up in your face.
- yummyfajitas 16y ago...but whether from LTCM, or more recently seeing so many CDS etc blow up,... I'm confused - how do CDS (did you mean CDOs) blowing up prove that a fractal model of the market is better than the standard Black Scholes + assorted tweaks model?