The 200-day moving average is arguably the most widely cited Technical Analysis indicator among financial media journalists, investment analysts, and portfolio managers alike. Roughly equivalent to ten months of trading, this measure of long-term trend has found uses in everything from trading to risk management.
A simple moving average is the average stock price over a past period. The most common moving average time periods are 50 days and 200 days. This is because, once you subtract weekends and holidays, 50 days approximates the number of trading days in a quarter and 200 days approximates a year.