The well-worn rhyme, "Sell in May and go away," has a basis in fact, FBN Securities Chief Market Technician JC O'Hara said Monday.
Looking at data over the past 20 years, O'Hara calculated average returns for the S&P 500 in the May-through-September time frame versus the other seven months.
"We've actually found, on average, over the last 20 years that the sell-in-May, the May through September bucket, was basically responsible for 0 percent of the S&P 500's returns. And I think that is very, very interesting, especially as we are right now. We're basically flat on the year. We're moving sideways. There's a lot of indecision," he said on CNBC's "Halftime Report."