“Sell in May and go away” is a classic bit of stock trading wisdom and in the interconnected world of markets it applies to all risk assets.

Think folksy rhymes don’t have a place in modern markets? Think again.

May has been a terrible month for stocks each year since 2009. May 2010 and May 2012 were two of the worst on record.

SP500 May 2010
SP500 May 2011
SP500 May 2012

Interestingly, the day to sell stocks might not be until tomorrow. The S&P 500 has gained (or posted a significant intraday gain) on the first trading day of May for 9 consecutive years.