As expected of the Christmas rally, the US stock market exhibits many ironclad rules that are widely accepted by the market. These rules don't guarantee a rise, but they do offer a high success rate. For example, historical statistics show a near 80% success rate for Christmas rallies, proving it's not just a matter of luck. 1. Quadruple witching days release settlement pressure. After settlement, the market's technical selling pressure and hedging constraints disappear, often leading to a rebound due to the removal of resistance. 2. To pursue impressive institutional performance, fund managers buy the best-performing stocks of the year at the end of the year (such as the AI leader in 2025) while eliminating underperforming stocks. 3. Tax strategy: US investors often sell loss-making stocks at the end of December to offset taxes. Entering January, selling pressure decreases sharply, funds flow back into the market, and combined with new year pension fund injections, this creates a catch-up rally.