Bollinger Bands - Volatility & Mean Reversion
Learn Bollinger Bands - how to trade the squeeze, band walks, and mean reversion strategies with GarudaAlgo.
What are Bollinger Bands?
Bollinger Bands were developed by John Bollinger in the 1980s. They consist of three lines that create a channel around price, automatically widening during volatile periods and contracting during calm periods.
Upper Band
SMA + (2 × StdDev)
Middle Band
20-period SMA
Lower Band
SMA - (2 × StdDev)
Middle Band = 20-period Simple Moving Average (SMA)
Upper Band = Middle Band + (2 × 20-period Standard Deviation)
Lower Band = Middle Band - (2 × 20-period Standard Deviation)
Statistically, about 95% of price action should remain within the bands (2 standard deviations). Prices touching or exceeding the bands are considered statistically significant.
How to Interpret Bollinger Bands
Key Concepts
- Band Width: Wide bands = high volatility, narrow bands = low volatility
- The Squeeze: When bands contract tightly, a big move is often coming
- Band Walk: In strong trends, price can "walk" along the upper or lower band
- Mean Reversion: Price tends to return to the middle band (equilibrium)
Bullish Signals
- Price bounces off lower band
- Squeeze breakout to the upside
- Price walks along upper band (strong trend)
Bearish Signals
- Price rejected at upper band
- Squeeze breakout to the downside
- Price walks along lower band (strong trend)
The Squeeze
- Bands contract to narrow width
- Indicates consolidation
- Explosive move often follows
Common Mistakes
- Don't trade touches blindly — A touch of upper/lower band is NOT automatically a signal
- Trending markets ≠ reversals — In trends, price can stay extended at bands
- Use with other indicators — Bollinger Bands work best with RSI/momentum confirmation
How GarudaAlgo Uses Bollinger Bands
GarudaAlgo Enhancement
GarudaAlgo monitors Bollinger Bandwidth to detect squeeze conditions and uses band position combined with RSI to confirm overbought/oversold conditions before signaling reversals.
What GarudaAlgo Analyzes
- Price Position: Above upper, below lower, or within bands
- Percent B (%B): Where price is relative to bands (0-1 scale)
- Bandwidth: Current band width for volatility assessment
- Squeeze Detection: Identifies low-volatility consolidation
- Band Slope: Direction of middle band for trend
- W-Bottoms / M-Tops: Classic Bollinger Band patterns
| Parameter | Default Value | Description |
|---|---|---|
| Period | 20 | SMA and StdDev calculation period |
| Standard Deviation | 2.0 | Multiplier for upper/lower bands |
| Squeeze Threshold | Dynamic | Based on historical bandwidth |
Trading Strategies
Strategy 1: Mean Reversion (Range Trading)
- Identify ranging market (flat middle band, no clear trend)
- Sell when price touches upper band + RSI > 70
- Buy when price touches lower band + RSI < 30
- Target the middle band, stop beyond the touched band
Strategy 2: Squeeze Breakout
- Identify squeeze (bands at narrowest in 120+ periods)
- Wait for price to close outside bands
- Enter in direction of breakout
- Expect expansion move, ride the band walk
Strategy 3: W-Bottom / M-Top Patterns
- W-Bottom: Price makes low at lower band, rallies, makes second low NOT at band
- Second low holding above band = bullish divergence
- M-Top: Opposite - first high at band, second high fails to reach band
- Classic reversal setups when combined with momentum divergence
Best Practices
- Match strategy to market type — Mean reversion in ranges, band walks in trends
- Combine with RSI — Band touch + extreme RSI = higher probability
- Watch the squeeze — Tight bands = upcoming volatility expansion
- Middle band is key — Acts as dynamic support/resistance
- 20/2 is standard but adjustable — Use 10/1.5 for faster signals, 50/2.5 for longer-term