The U.S. stock exchanges are open Monday through Friday, 9:30 a.m. to 4:00 p.m. Eastern Standard Time, except on designated holidays. Holidays may be a specific date, such as December 25 for Christmas, or a specific day, such as the first Monday in September for Labor Day. The markets also close for significant national events.
Holiday history has changed since the stock market began. Martin Luther King, Jr., Day, for instance, became a national holiday in 1986, but the stock exchanges only began closing for this holiday in 1998. Memorial Day originally was observed on May 30 instead of the last Monday in May.
World War I
When World War I began in 1914, the only U.S. stock market was the New York Stock Exchange, and it closed for nearly five months. The NYSE also halted trading for two days after the end of World War II to celebrate victory.
Funerals and Assassinations
The markets close for funerals of former presidents, and also closed for the funeral of Martin Luther King, Jr., on Apr. 9, 1968. They closed for the rest of the day after John F. Kennedy was shot on November 22, 1963, and for the rest of the day after the assassination attempt on Ronald Reagan on Mar. 30, 1981.
After the September 11, 2001 attack on the World Trade Center, the stock markets stopped trading until September 17.
Additionally, the stock market has safeguards called circuit breakers, originally designed to halt trading after specific point drops in the Dow Jones Industrial Average during a single day. This point-drop rule caused trading to stop on Oct. 27, 1997, even though the decrease was only about 7 percent. The rule was subsequently changed to respond to percentage drops rather than point drops.
The markets have also closed due to bad weather. They have closed early or opened late on occasion because of snowstorms, for instance, and were closed on Sept. 27, 1985 because of Hurricane Gloria.