This decade is strewn with examples of bright people who thought they built a better mousetrap that could consistently extract abnormal returns from the financial markets. Some succeed for a time. But while there may occasionally be mis-configurations among market prices that allow abnormal returns, they do not persist.
Alan GreenspanThe very nature of finance is that it cannot be profitable unless it is significantly leveraged... and as long as there is debt, there can be failure and contagion.
Alan Greenspan