Is there a good reason for 'Sell in May and go away?' Maybe more than one.

"Sell in May and go away" isn't science. Some market pundits say it's no more than a historical trading anomaly and others believe that this year will be an exception for a variety of reasons. But there is a good deal of trading history to support investors who fear a stock market slowdown during summer months. We used Kensho to take a look back at summer periods beginning in 2000.