Why the 200d SMA is important: The Simple Moving Average (SMA) is the average price of an asset over a certain period of time. It is calculated by adding up the closing prices over a certain number of time periods, and then dividing by that number of time periods. SMA’s are used to measure momentum. The most watched SMA is the 200 day, it is widely recognized as the dividing line between bull and bear territory. The primary trend is considered to be up as long as the market is trading above its 200-day moving average but this trend turns bearish whenever the market closes below this average.