"Sell in May and go away."

Spencer Platt, Getty Images

It's an old Wall Street saying that means to dump stocks and hit the vacation trail, but it might not apply this May.

A lot of the wisdom of, "sell in May and go away" is rooted in the fact that since 1950, most of the market's gains occur between November and April. The Dow has gained an average of 7.5 percent in that period over the years, but an anemic average gain of 0.3 percent has been measured between May and October.

Mercer County stock trader Ken Kamen counsels this one-size-fits all wisdom doesn't fit right now.

"The market has made new highs recently, and that's even with the last three or four Mays being down. So don't get 'head faked' out of this market."

He says investors will stay for the long haul. Traders, who try to keep up with lightning-fast computer transactions, will "get their heads handed to them."

Investors who bought stock on May 1 and held on to reinvesting dividends, had a return of 11.1% a year on average, topping the gain of the investors who sold in May and went away.