What are the Bollinger Bands in Technical Analysis?

Bollinger Bands are a popular technical analysis tool developed by John Bollinger in the 1980s. They are used to measure market volatility and identify potential overbought or oversold conditions in a security's price.

Components of Bollinger Bands

1. 

   Middle Band (SMA) – A Simple Moving Average (SMA) typically set to 20 periods (but adjustable).

• Formula:

  $$\text{Middle Band}=\text{SMA (20)}$$Middle Band=SMA (20)

2. Upper Band – The middle band plus two standard deviations (adjustable).

• Formula:

  $$\text{Upper Band}=\text{SMA (20)}+2\times \text{Standard Deviation (20)}$$Upper Band=SMA (20)+2×Standard Deviation (20)

3. Lower Band – The middle band minus two standard deviations.

• Formula:

  $$\text{Lower Band}=\text{SMA (20)}-2\times \text{Standard Deviation (20)}$$Lower Band=SMA (20)−2×Standard Deviation (20)

Key Concepts & Interpretation

• Volatility Indicator:

• When bands widen → high volatility.

• When bands contract (squeeze) → low volatility, often preceding a big price move.

• Overbought/Oversold Signals:

• Price near upper band → may be overbought (potential sell signal).

• Price near lower band → may be oversold (potential buy signal).

• Mean Reversion vs. Trend Continuation:

• In ranging markets, price tends to revert to the middle band.

• In strong trends, price can ride the bands, signaling momentum.

• Bollinger Squeeze:

• A tight contraction in bands suggests a potential breakout (direction confirmed by other indicators like volume or RSI).

Limitations

• Works best in volatile, trending markets but can give false signals in choppy conditions.

• Should be combined with other indicators (RSI, MACD, volume) for better accuracy.

Example Use Cases

• Swing Trading: Buying near the lower band, selling near the upper band in a range-bound market.

• Breakout Trading: Watching for a squeeze followed by a breakout with volume confirmation.