Bollinger Band Reversion
Mean reversion · Equity ETFs · Daily
The rules, in plain English
Bollinger Bands wrap price in a band based on recent volatility. This strategy buys when price falls below the lower band — stretched to the downside — and exits when price returns to the middle line. It is a textbook mean-reversion trade: buy the stretch, sell the return to normal.
The published backtest
| Total return | +487.0% |
|---|---|
| CAGR (annual growth rate) | +7.04% |
| Sharpe ratio | 0.42 |
| Maximum drawdown (worst peak-to-trough fall) | -35.2% |
| Win rate | 59.8% |
| Profit factor | 1.96 |
| Risk grade (our shorthand, from the published figures) | C |
| Asset class | Equity ETFs |
| Style | Mean reversion |
| Timeframe | Daily |
| Type | Weights |
— means no figure was published for this strategy. Ungraded and workflow entries publish diagnostics rather than a graded portfolio backtest, so some metrics are not published for them.
Honest verdict
Held up
This one made money in its published backtest, but modestly for the risk taken — look at the Sharpe ratio and the worst drawdown together before forming any opinion.
Worst drawdown in the published test: -35.2% — at its lowest point, a follower of this test would have been down that much from the peak before any recovery.
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Attribution: strategy and published backtest results from the QuantJourney open-source library (Apache-2.0), via quants.md — published backtest results by QuantJourney, reproduced with attribution. Results are hypothetical backtest results based on historical data; they are not live trading results and do not guarantee future performance. Educational content only — not financial advice, and not a recommendation to buy, sell, or hold any security.