These predictions and models work until they don't. And when they don't, they blow up in spectacular fashion. Look at Long Term Capital Management. It had big

These predictions and models work until they don't. And when they don't, they blow up in spectacular fashion. Look at Long Term Capital Management. It had big names behind it and the model/strategy made a lot of money, until I believe the Russian bond crisis caused the markets to act irrationally. Then everything they had invested in quickly went down the toilet, and it was big enough to almost cause a financial crisis.