A Santa Claus rally is a calendar effect that involves a rise in stock prices during the last 5 trading days in December and the first 2 trading days in the following January., ^{[1] [2]} According to the 2019 Stock Trader's Almanac, the stock market has risen 1.3% on average during the 7 trading days in question since both 1950 and 1969. ^{[2] [3]} Over the 7 trading days in question, stock prices have historically risen 76% of the time, which is far more than the average performance over a 7-day period.

However, in the weeks prior to Christmas, stock prices have not gone up more than at other times of the year. ^{[4] [5]}

The Santa Claus rally was first recorded by Yale Hirsch in his Stock Trader's Almanac in 1972. ^[6]

The Dow Jones Industrial Average has performed better in years following holiday seasons in which the Santa Claus rally does not materialize. ^{[7] [3]}

There is no generally accepted explanation for the phenomenon. ^[2] The rally is sometimes attributed to the following:

• Increased investor purchases in anticipation of the January effect ^[2]
• Lighter volume due to holiday vacations makes it easier to move the market higher ^[3]
• A slow down in tax-loss harvesting that depresses prices at the beginning of December ^[3]
• Short sellers / pessimistic investors tend to take vacations around the holidays ^[2]

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