Bollinger Bands: range, squeeze and band walks
Bollinger Bands draw a 20-period simple moving average with an upper and lower band two standard deviations away. About 90 to 95% of closes fall inside the bands, so a touch marks a statistically stretched move. Narrow bands (a squeeze) precede expansion; in strong trends price can walk along a band for many candles.
What the bands encode
Band width is volatility. When the market is quiet the bands pinch together; when it moves they widen. The middle band is the 20-period mean, a natural pullback target inside a trend. A close outside a band is unusual, not wrong: it happens on every real breakout.
Squeeze and expansion
The most useful Bollinger pattern in crypto is the squeeze: bands at their narrowest in weeks, then a candle closes outside. The direction of that first close often sets the next leg. The second-most useful is the band walk, where price hugs the upper band during a squeeze of shorts; selling there because it "looks overbought" is a common paper-desk mistake.
How the SIMMENT desk uses them
The chart draws BB 20/2 (toggle BB). In the engine score a touch of the lower band adds two bullish votes, the upper band two bearish, and being above or below the middle band one vote either way. It is range context, never a fill reason on its own.
Quick answers
Should I buy the lower Bollinger Band?
Only when the trend and support votes agree. In a downtrend the lower band keeps moving down with price.
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Educational content. Simulated trading only. Not financial advice. Updated 2026-09-06.