Bollinger Squeeze strategy: rules and backtest
Bollinger Squeeze is a counter-trend strategy: it buys at the lower Bollinger band and sells at the upper one, betting on a return to the mean.
| Parameter | Value |
|---|---|
| Type | Mean-reversion |
| Timeframe | W1+ |
| Complexity | Intermediate |
| Instrument | USD/JPY |
How the signal works
Bollinger Bands mark a statistically unusual deviation of price from its mean. The strategy reads a touch of a band as overextension and enters against the move, targeting a return to the central SMA(20). This works while the market oscillates within a range.
The key limitation is built into the very idea: in a trend, price can ride a band for a long time, and the counter-trend entry turns into a run of losses. So the strategy is profitable in a calm market and dangerous in a strong move.
Verification on real data
This strategy’s rule is run on real quotes with no parameter fitting to history. The rule tested was “Bollinger Squeeze: reversion from the bands to the mean”:
- Long on a close below the lower Bollinger band (20, 2σ).
- Short on a close above the upper band.
- Exit when price returns to the mean (SMA20).
Pros and cons
- A high share of winning trades in a ranging market.
- Clear entry and exit levels — the band and the mean.
- Band width self-adjusts to volatility.
- Unprofitable in a trend: price rides the band without returning.
- It catches a "falling knife" — entering against a strong move.
- It requires a reliable trend filter, which the base version lacks.
Pitfalls
Bollinger Squeeze ruins the trader in a trend: a touch of the upper band in a rising market is the norm, not a sell signal, and a run of shorts against the trend quickly eats the account. John Bollinger himself warned against reading the bands this way. The strategy is safe to use only with a filter that disables it when ADX is high.
Who it suits
For traders of ranging instruments who understand that the price of a high win rate is a rare large loss in a trend. It requires a strict market-state filter.
Frequently asked questions
Why does the strategy buy on a decline?
It is counter-trend: a touch of the lower band is read as a statistically overextended move that more often returns to the mean. This works in a range and breaks in a trend.
What if price rides the band?
That is a sign of a strong trend, and it is ruinous for the strategy: a run of counter-trend entries produces losses. That is exactly why a filter is needed to disable the strategy in a pronounced trend.
Why is the win rate high in the backtest?
On a calm sample, returns to the mean trigger often, hence the high win rate. But that metric is deceptive: a single extended trend can wipe out the profit of many small winning trades.