Introduction to Bollinger Bands
Bollinger Bands are a technical analysis tool developed by John Bollinger in the 1980s. They are used primarily in trading to measure the ‘highness’ or ‘lowness’ of the price of a security relative to previous trades. Bollinger Bands consist of a middle band with two outer bands. The middle band is a simple moving average, while the outer bands are standard deviations of the middle band.
Understanding Bollinger Bands
Bollinger Bands are a volatility indicator. When the markets become more volatile, the bands widen; during less volatile periods, the bands contract. Essentially, they provide relative definitions of high and low that are adaptive to market volatility.
Components of Bollinger Bands
Bollinger Bands consist of three lines:
1. The Middle Line: This is a simple moving average (SMA) of the security’s price. The standard period for this is 20 days, although traders can use whatever period they find most useful.
2. The Upper Band: This is calculated by adding two standard deviations to the middle line.
3. The Lower Band: This is calculated by subtracting two standard deviations from the middle line.
Using Bollinger Bands in Trading
Bollinger Bands can be used in numerous ways by traders. Here are some of the most common strategies:
1. Bollinger Bounce
The basic idea of a Bollinger Bounce is that the price tends to return to the middle of the bands. That is, when the price of a security is at the upper band, it is considered ‘overbought’, and it is likely to revert back towards the middle. Conversely, when it is at the lower band, it is considered ‘oversold’, and is likely to revert back to the middle.
2. Bollinger Squeeze
A Bollinger Squeeze indicates a period of low volatility and is considered by traders to be a potential sign of future increased volatility and possible trading opportunities. The squeeze is identified when the bands come closest together.
3. Riding the Bands
Another strategy is to stay with the trend as long as the price remains in the upper band for an uptrend and the lower band for a downtrend. This strategy works well in trending markets but can lead to losses in ranging markets.
Limitations of Bollinger Bands
While Bollinger Bands can be a useful tool, like all trading indicators, they have their limitations. They are not designed to provide standalone buy or sell signals, and they should be used in conjunction with other technical analysis tools. Furthermore, in trending markets, the bands may not provide accurate indications of whether a security is overbought or oversold.
Conclusion
Bollinger Bands are a versatile and useful tool for traders. They can help identify potential buy and sell signals, provide a measure of market volatility, and offer a way to visualize the price movement of a security. However, like all trading tools, they should be used as part of a comprehensive trading strategy, and not in isolation.