As goes January, so goes the year. This particular phenomenon is what is referred to as the January Barometer. To test this theory, today’s chart presents the average performance of the S&P 500 one, three, six, and 11 months following a January gain (blue bars) and following a January loss (gray bars). The chart illustrates that the S&P 500 has performed much better (on average) during the months following a January gain. In fact, 11 months following a January gain; the S&P 500 was up 89% of the time. FYI - The S&P 500 was up 1.4% in January 2007.