Mean reversion · daily rule · Healthcare
Bollinger Reversion on GE HealthCare
What the play says
GEHC with the play, last two years
Shading shows the play's call from the close that triggered it.
Growth of $10,000 since 2023
Log scale. After trading costs, with T-bill interest while out.
The record
The play against buying and holding GEHC over exactly the same dates, after costs.
| Play, since 2023 | Hold, since 2023 | Play, 5 yrs | Hold, 5 yrs | |
|---|---|---|---|---|
| Annual return | +13.4% | +2.4% | +13.4% | +2.4% |
| Total return | +60% | +9% | +60% | +9% |
| Worst drawdown | −22.7% | −37.4% | −22.7% | −37.4% |
| Volatility | 18.0% | 32.4% | 18.0% | 32.4% |
| Sharpe ratio | 0.54 | 0.10 | 0.54 | 0.10 |
| Time invested | 25% | 100% | ||
| Switches per year | 9.7 | 0 |
Every call, graded
Right on 24 of 36 closed calls (67%). In calls averaged +2.2%; out calls saw GEHC move −1.4% on average.
| Called | Call | Price | Until | GEHC moved | Result |
|---|---|---|---|---|---|
| Sep 28, 2026 | OUT | $66.78 | now | +3.0% | open |
| Sep 3, 2026 | IN | $69.72 | Sep 28, 2026 | −4.2% | ✕ wrong |
| Jul 28, 2026 | OUT | $64.11 | Sep 3, 2026 | +8.8% | ✕ wrong |
| Jul 22, 2026 | IN | $61.38 | Jul 28, 2026 | +4.5% | ✓ right |
| Jun 23, 2026 | OUT | $63.68 | Jul 22, 2026 | −3.6% | ✓ right |
| Jun 17, 2026 | IN | $61.12 | Jun 23, 2026 | +4.2% | ✓ right |
| May 20, 2026 | OUT | $64.22 | Jun 17, 2026 | −4.8% | ✓ right |
| Apr 29, 2026 | IN | $59.45 | May 20, 2026 | +8.0% | ✓ right |
| Apr 1, 2026 | OUT | $71.90 | Apr 29, 2026 | −17.3% | ✓ right |
| Mar 6, 2026 | IN | $74.19 | Apr 1, 2026 | −3.1% | ✕ wrong |
| Feb 4, 2026 | OUT | $82.54 | Mar 6, 2026 | −10.1% | ✓ right |
| Jan 20, 2026 | IN | $78.75 | Feb 4, 2026 | +4.8% | ✓ 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 37 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.