Where's Santa?

Markets are three days into the highly anticipated "Santa Claus" rally, which is statistically one of the most consistent seven-day positive stretches of the year for the S&P 500.

But stocks have not been in the holiday spirit. All three major averages sold off Friday, with the Nasdaq falling nearly 1.5%.

Since 1950, the S&P 500 has risen 1.3% during the seven trading days beginning Dec. 24, well above the typical seven-day average of 0.3%, according to LPL Financial chief technical strategist Adam Turnquist. History has shown that if Santa does come and the S&P 500 posts a positive return during the time period, then January is typically a positive month for the benchmark index and the rest of the year averages a 10.4% return.

When the S&P 500 is negative during that time frame, January usually doesn't end in the green, and the return for the upcoming full year averages just 5%, per Turnquist. Three days into this year's Santa Claus period, which will close on Friday, Jan. 3, the S&P 500 is down less than 0.1%

While history may be flashing a warning sign, it's notable that last year the Santa Claus rally didn't materialize. January started poorly too. Still, the S&P 500 is still set to end the year up more than 20%.