The idea
Bollinger Bands sit two standard deviations either side of a 20-period average. In a market without a trend, a close outside a band is an unusually stretched move, and price often swings back toward the middle.
The strategy waits for that stretch to end: after a close below the lower band, it buys the first close back inside the bands and targets the middle band, the 20-period average. It is the opposite of the squeeze breakout, and only belongs in sideways markets.
Watch it play out
Step by step
The rules
Setup
- Bollinger Bands (20, 2). The middle band is flat, and price has crossed it back and forth recently.
Entry
- After a close below the lower band, buy at the first close back inside the bands.
Stop-loss
- Under the lowest low of the move outside the band.
Target
- The middle band (the 20-period average).
Filters that help
- Skip it when the bands are widening fast: that is a breakout, not a stretch.
- Prefer setups at a known support level.
Why it can work
In a range, there is no new information pushing price one way, so moves to the edges tend to be overreactions that fade. Waiting for the close back inside avoids buying while the selling is still in full flow.
The bands measure the market's own recent volatility, so the same rule adapts to calm and wild periods without changing any number. The cost is that the bands also widen quickly at the start of a trend, which is exactly when this strategy should stop.
Worked example
EUR/USD has ranged for a week. It closes below its lower band, then the next candle closes back inside at 1.0912. The low of the move was 1.0896, so the stop goes at 1.0893, 19 pips away. The middle band, the target, is at 1.0945.
Risking 100 dollars, that is 0.52 lots, aiming for 33 pips, about 1.7R.
When it works, when it fails
Works best
In quiet, range-bound markets with a flat middle band.
Struggles
At the start of trends: price can ride the band for days, and each 'stretch' gets more stretched. A close outside the band is also how breakouts begin.
Common mistakes
- Buying a close below the band in a downtrend.
- Not waiting for the close back inside.
- Moving the target beyond the middle band.
Variations
- Double Bollinger Bands
- Adding bands at one standard deviation as well, and only trading reversions when price is between the 1 and 2 bands.
What the evidence says
Evidence: Popular, untestedWidely used, but no rigorous public testing. An idea to test yourself.
Short-term reversals in quiet markets are a real tendency in some markets, but this specific Bollinger rule has no rigorous public study after costs. Even John Bollinger, who created the bands, describes closes outside them as possible continuation signals, not automatic reversals.
Treat it as a range tool to test, and know the market type before using it.
Questions
- How do I know the market is ranging?
- A flat 20-period average, price crossing it back and forth, and bands that are neither widening nor squeezing. When the average slopes clearly, the market is trending and this strategy should be left alone.
- Does Bollinger reversion work on crypto?
- Crypto ranges too, but it also trends hard and stretches far beyond the bands. Wider stops, smaller sizes and a strict range filter matter even more there.
- Is touching the lower Bollinger Band a buy signal?
- Not by itself. In a trend, price can walk down the lower band for a long time. The strategy needs a sideways market and a close back inside the bands.
- Where should the target be?
- Usually the middle band. Aiming for the opposite band asks for a full swing across the range, which happens less often.
- What is the difference from the squeeze?
- The squeeze trades breakouts after quiet spells; this trades returns to the average in ranges. They are opposite bets for opposite conditions.