Bollinger lower band
The lower Bollinger Band sits two standard deviations below the 20-period simple moving average and marks the lower volatility zone of price.
The lower band is the downside counterpart of Bollinger Bands: the 20-period simple moving average minus two standard deviations of price over the same window. It moves away from the average when volatility rises and tightens when the market calms down. A price touching or breaking the lower band is statistically low relative to its behaviour over the last 20 periods : which can herald either a bounce or a bearish acceleration.
How to read and use it
In a rangebound market, a touch of the lower band is often treated as a bearish excess zone, with a reversion expected towards the central moving average. In an established downtrend, by contrast, price can ride the lower band for a long time: selling every touch would be counterproductive, and buying every touch would mean fighting the trend. This is a classic screener use case: in Screener.Trading you can filter assets whose price closes below the lower band, then add a trend or momentum filter (RSI, long moving average) to separate excesses from genuine breakdowns.
A close below the lower band is not an automatic buy signal: in a strong downtrend, prices can stay glued to the band for extended stretches.
Keep exploring
- FeatureThe multi-indicator, multi-timeframe screenerCombine technical indicators, timeframes and comparison operators to keep only the assets that match your strategy exactly.
- FeatureAutomated scans: your screeners on autopilotBots watch the market for you: they re-run your screeners at every candle close and e-mail you the moment an asset matches.
- IndicatorBollinger BandsA volatility envelope around a moving average: the bands widen when the market gets busy and tighten when it calms down.
- IndicatorSimple Moving Average (SMA)The oldest and most widely used trend indicator: an average of recent closes that smooths out market noise and acts as a dynamic reference line.
- IndicatorRSI (Relative Strength Index)The most popular momentum oscillator: it bounds the strength of a move between 0 and 100 and flags overbought and oversold conditions.
- GlossaryBollinger upper bandThe upper Bollinger Band sits two standard deviations above the 20-period simple moving average and marks the upper volatility zone of price.
- GlossaryTimeframeA timeframe is the duration each candle on a chart represents (from one minute to several months) and sets the horizon of the analysis.
- GuideBuilding your first screener, step by stepHow to turn a strategy idea into objective rules, pick the right asset universe, read scan results and iterate until you get a genuinely actionable list of opportunities.