Traders also pointed to year-end tax selling and the simultaneous expiration of stock options, stock index futures and index options contracts - known as triple witching - as potential causes for volatility.
"People are closing out their positions on a day like this because we have long weekend coming up for Christmas next week, especially institutions as they clear their books, and also a combination of year-end tax selling," said Peter Cardillo, chief market economist at Spartan Capital Securities in New York.
"The overall mood getting into next year is going to be positive, but everything is based on the macroeconomic outlook." Traders work on the floor of the New York Stock Exchange in New York City, U.S., November 29, 2021. REUTERS/Brendan McDermid