Investors shouldn't worry about the Dow dropping 135 points Thursday—the biggest drop since early November—because the first trading day following a great year remains a "coin toss," Sam Stovall of S&P Capital IQ told CNBC on Friday.
Stovall, S&P Capital's chief equity strategist, said that dating back to 1929, half of the first trading sessions posted losses following years in which the market gained more than 20 percent.
"So you shouldn't look to much into the first-day trading," Stovall said on "Squawk on the Street." "Being a student of history, my feeling is you look to history as a guide. Obviously it's never gospel, but you don't look to one day alone. … There's still a good chance that we have a good year, not a great year."
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