Using Bollinger band and Keltner Band for Technical Analysis

The Bollinger band with the following characteristics. the bands are used for finding the over bought and oversold areas based on the price and volatility. the formation is based on the SMA in the middle and the upper one is the line that shows twice the standard deviation and the lower one is the one that shows the minus two times of standard deviation. In general, the Bollinger band works well at the time that the market is bound. for the stocks like the Business Development Companies or Index trading, it can be a good approach.