Bollinger Bands®

Bollinger Bands were created by John A. Bollinger. They compare volatility and relative price levels over a period time. The indicator consists of three bands designed to encompass the majority of a security's price action: a Moving Average in the middle, an upper band (moving average plus x standard deviations) and a lower band (moving average minus x standard deviations).

Since the bands encompass normal price behavior, it is possible to identify abnormal price levels; the bands squeeze together when volatility is low and spread apart when volatility is high.

Read more about Bollinger Bands at www.BollingerBands.com.

Bollinger Bands® are the registered trademark of John Bollinger, who developed them.