As one of the most famous seasonal phenomena in the US stock market, the Christmas rally was first proposed in 1972. Historical data shows strong stability over the past few decades.

Between 1950 and 2024, over 75 years, the S&P 500 index has seen 58 instances of closing gains, with a probability of increase reaching 77.33%, and an average increase of 1.33%, far exceeding the market's average return level of 0.3% over a typical seven-day trading period. If we narrow the timeframe a bit, in the twenty years from 2005 to 2024, there were 13 years with gains, with a probability of increase of about 65% and an average increase of 0.96%.