The Christmas Grinch in trading refers to a bearish market pattern or selloff that occurs around the Christmas holiday period, opposite of a Santa Claus Rally. It describes when markets decline during the typically bullish late December period, catching investors off guard. Low holiday liquidity can amplify these moves, and a failed Santa Claus Rally is sometimes viewed as a cautionary signal for market performance in the year ahead.
Example
“The Christmas Grinch struck in late December as markets sold off sharply, dashing hopes of the traditional year-end Santa Claus Rally.”