Compared to its harsh December performance, when the S&P lost about 9 percent, the market bounced back in January.
During that month, the S&P 500 recouped almost all of its month-prior loss, gaining about 8 percent.
Since 1980, there have been only five other occurrences in which the S&P 500 gained between 5% and 10% in January, according to a CNBC analysis using Kensho.
This tended to be a positive sign for the remainder of the year.
In the following "February to end-of-December" period, the index surged.
It's added an average of almost 14% more, trading positively 80% of the time.