The stock market is open for business between 9:30 a.m. and 4 p.m. Monday to Friday. Billions of shares are traded in the American markets, making them very liquid and efficient.

Presidents' Day is Monday, Feb. 17 and some services, along with federal and Florida state offices, will be closed. For the federal government, though, the holiday is called Washington's Birthday.

All post office locations are slated to be closed on that day for President’s Day. Even in the states — Delaware, Florida, ...