Built from a moving average plus and minus standard deviation, the bands widen and narrow with volatility itself — touching the upper band is as often strength as it is exhaustion.
John Bollinger developed bands that widen and narrow automatically with actual volatility, unlike older fixed-percentage envelopes.
Bollinger repeatedly clarified that tags on the upper band, in a strong trend, mean strength, not automatically "sell".
Traders noticed that bands squeezing unusually tight often preceded a sharp move — a genuinely useful, if directionless, warning.
Serious use today reads the trend and the squeeze before ever reacting to a single band touch.
A middle band (usually a 20-day SMA) sits between an upper and lower band set two standard deviations away — so the bands widen in volatile stretches and narrow in quiet ones.
In a genuinely strong trend, price can hug and repeatedly tag the upper band for an extended stretch — a sign of strength, not an automatic reversal cue.
When the bands pinch to an unusually tight width, a bigger move is often coming — but the squeeze itself carries no directional bias of its own.
Through that stretch, price repeatedly tagged and rode the upper band for weeks — genuine strength, not an overbought warning.
Ahead of that stretch, the bands pinched to an unusually tight width before a genuine breakout followed — the squeeze doing exactly what it warns about.
Price has been walking the upper Bollinger band for two straight weeks in a strong, sustained uptrend. A trader shorts the fifth touch. Sound?
The bands have pinched to their tightest width in months. A trader immediately buys, assuming the squeeze must resolve upward. Fair?
A trader draws a horizontal line at today's upper band level and expects price to respect it as resistance for weeks to come. Reasonable?
Price and the bands, watched tick by tick on the left — and the mark it leaves in the ledger on the right. A genuine band-ride uptrend, a tight squeeze before a breakout — and a naive upper-band sell that got run over.
Price tags the upper band. Judge whether the broader trend is genuinely strong — then call it: ride the strength, or fade the exhaustion.
The classic error is treating the upper band like a fixed overbought ceiling. The discipline is mechanical: check the trend before reacting to any single touch, then treat a squeeze as a warning of volatility, never a directional prediction.
Bollinger built a band that measures how much price is actually moving, not what it should do next. Read the trend and the squeeze together, and let the band describe, never decide.
Volatility clusters, and calm breeds storm.