The open, or opening price, is one of four major data points used in stock market day trading. The other three are known as low, high, and close, and all four are referred to collectively as OHLC. Historically, stock market trading took place during regular market hours, which were frequently only between 9 a.m. and 4 p.m. local time, with markets closed on weekends. Because cryptocurrency markets are open 24 hours a day, 7 days a week, the OHLC is still included on most charting platforms to represent the opening time of the regular stock market each day.