Using Bollinger Band Contractions to Watch for Volatility Breakouts

Summary

The document explains the Bollinger Band squeeze as a way to identify periods when price volatility has contracted. It describes the conventional bands as a 20-period simple moving average with upper and lower boundaries set two standard deviations away. When those boundaries draw closer, the market may be consolidating, with reduced volatility and less directional pressure. A later expansion can alert a trader that conditions are changing and a larger move may be developing.

The squeeze does not indicate whether the eventual move will be upward or downward. The document recommends seeking confirmation from trading volume or other technical signals, such as candlestick patterns or RSI, before judging direction. It offers a qualitative explanation rather than empirical evidence: no rules are given for defining squeeze duration, measuring band width, entering or exiting trades, or managing risk. A contraction therefore serves as a volatility watch signal, not a reliable prediction that a strong breakout or trend will follow.

Key ideas

• Bollinger Bands use a moving average as the middle band and standard deviation-based outer bands.
• A squeeze occurs when the outer bands contract, signaling a period of lower volatility.
• Band expansion after a contraction may indicate that volatility is returning.
• The squeeze provides no directional forecast, so other evidence may be needed to assess a move.
• The document gives no tested entry, exit, or risk-management rules.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.