Interesting article publishe at National Post/Financial Post...

"Night traders outperform

Posted: March 13, 2009, 8:19 AM by Jonathan Ratner

It pays to sleep late-- if you are an equity investor that is. It seems that all the returns from investing in the S&P 500 using a buy and hold strategy came at night, in aftermarket trading, according to a recent Goldman Sachs report.

Investors who bought the S&P 500 after it closed and sold before it opened would have earned a 309% cumulative return since 1993, markedly better than the 80% return for a true buy and hold strategy since that time. Investors who held the market only during trading hours would have been hit with a 58% cumulative loss..."

Complete article is here .