Bollinger Bands

Bollinger Bands, a chart indicator developed by John Bollinger, are used to measure a market's volatility.
Basically, this little tool tells us whether the market is quiet or whether the market is LOUD! When the market is quiet, the bands contract and when the market is LOUD, the bands expand.


One thing you should know about Bollinger Bands is that price tends to return to the middle of the bands. That is the whole idea behind the Bollinger bounce.

Because standard deviation is a measure of volatility, Bollinger Bands adjust themselves to the market conditions. When the markets become more volatile, the bands widen (move further away from the average), and during less volatile periods, the bands contract (move closer to the average). The tightening of the bands is often used by technical traders as an early indication that the volatility is about to increase sharply.

This is one of the most popular technical analysis techniques. The closer the prices move to the upper band, the more overbought the market, and the closer the prices move to the lower band, the more oversold the market.