Updated at 6:40 a.m. ET
The stock market was only open for half a day Monday, and that was more than enough time for the Dow Jones Industrial Average to drop 2.9 percent to 21,792.20, breaking 1918's record for the worst Christmas Eve performance.
Other U.S. indexes fell too. The Nasdaq lost 2.2 percent to 6,192.92. The Standard & Poor's 500 index fell 2.7 percent to 2,351.10.