Mean reversion · daily rule · Consumer & retail
Bollinger Reversion on BRP
What the play says
DOO with the play, last two years
Shading shows the play's call from the close that triggered it.
Growth of C$10,000 since 2013
Log scale. After trading costs, with T-bill interest while out.
The record
The play against buying and holding DOO over exactly the same dates, after costs.
| Play, since 2013 | Hold, since 2013 | Play, 5 yrs | Hold, 5 yrs | |
|---|---|---|---|---|
| Annual return | +2.5% | +9.2% | +6.9% | −7.7% |
| Total return | +38% | +222% | +39% | −33% |
| Worst drawdown | −67.9% | −73.6% | −42.1% | −62.5% |
| Volatility | 25.4% | 41.7% | 22.9% | 42.2% |
| Sharpe ratio | 0.15 | 0.38 | 0.24 | −0.06 |
| Time invested | 25% | 100% | ||
| Switches per year | 8.5 | 0 |
Every call, graded
Right on 69 of 113 closed calls (61%). In calls averaged +1.1%; out calls saw DOO move +4.2% on average.
| Called | Call | Price | Until | DOO moved | Result |
|---|---|---|---|---|---|
| Oct 9, 2026 | IN | C$75.60 | now | −1.2% | open |
| Sep 4, 2026 | OUT | C$92.77 | Oct 9, 2026 | −18.5% | ✓ right |
| Aug 26, 2026 | IN | C$83.41 | Sep 4, 2026 | +11.2% | ✓ right |
| May 11, 2026 | OUT | C$77.51 | Aug 26, 2026 | +7.6% | ✕ wrong |
| Apr 15, 2026 | IN | C$69.42 | May 11, 2026 | +11.7% | ✓ right |
| Mar 26, 2026 | OUT | C$92.31 | Apr 15, 2026 | −24.8% | ✓ right |
| Feb 27, 2026 | IN | C$99.18 | Mar 26, 2026 | −6.9% | ✕ wrong |
| Nov 21, 2025 | OUT | C$89.48 | Feb 27, 2026 | +10.8% | ✕ wrong |
| Oct 31, 2025 | IN | C$87.06 | Nov 21, 2025 | +2.8% | ✓ right |
| May 7, 2025 | OUT | C$47.11 | Oct 31, 2025 | +84.8% | ✕ wrong |
| Apr 16, 2025 | IN | C$45.30 | May 7, 2025 | +4.0% | ✓ right |
| Apr 9, 2025 | OUT | C$51.78 | Apr 16, 2025 | −12.5% | ✓ right |
An in call is right when the price rose before the next call; an out call is right when it fell. The latest 12 of 114 calls shown.
How the play works
- In on a close below the lower band (20-day average − 2 standard deviations).
- Out on a close above the 20-day average.
This runs against Bollinger's advice that tags of the bands are not signals. It is shown because so many traders use it.
The case against
Valeriy Zakamulin tested moving-average timing on up to 155 years of U.S. stock data and found no statistically significant edge in the second half of that record. The rules earned their keep in a few severe bear markets and lagged buy and hold for long stretches in between.