Thanksgiving week has a notorious “holiday fueled” bullish bias as do the last seven trading days of the month. However, as you can see from the tables here of the history of the Thanksgiving trade the bullish bias has weakened over the last several years, most notably on Wednesdays and Fridays.
First published in the 1987 Stock Trader’s Almanac, the Wednesday before and the Friday after Thanksgiving combined were up 34 times in 35 years. The only S&P 500 decline was in 1964. Subsequently, this trend changed. In the 35 years since 1987, there have been 10 declines and 26 advances. See 2024 Stock Trader’s Almanac page 106 for more.