Backtest: When XOM's 5-day percentage change underperforms CVX's by more than 2 percent...
The pair trade sounds tidy: when Exxon lags Chevron by too much over five days, buy the laggard and ride the mean-reversion. That logic — supermajor relative moves overshoot, then snap back — is plausible in a sector where two mega-caps often trade as substitutes. But this backtest puts that intuition to the test with real numbers, and the verdict is more complicated than the setup suggests.
Across 31 closed trades, the strategy banked a positive return, winning 61.3% of the time. Yet that edge wasn't enough: over the same window, buy-and-hold SPY was up far more, leaving the strategy trailing the benchmark by over 43 points. A 25% raw gain can look respectable until weighed against what passive capital did.
Below: every trade, the spread mechanics, the best and worst outcomes, and why the win rate didn't translate into relative performance. The full evidence is in the analysis.
When XOM's 5-day percentage change underperforms CVX's by more than 2 percentage points, buy XOM at the close; exit after 5 trading days or when XOM's 3-day percentage change beats CVX's by at least 1 percentage point, whichever comes first. Supermajor relative-price gaps overshoot, so the XOM-CVX spread tends to mean-revert as sector flows rotate between the two large-cap energy names.
How this was measured
This is a simulated backtest generated from the plain-English strategy below, executed bar-by-bar on historical market data using the price + news data mode with $100,000 starting capital. Strategy: When XOM's 5-day percentage change underperforms CVX's by more than 2 percentage points, buy XOM at the close; exit after 5 trading days or when XOM's 3-day percentage change beats CVX's by at least 1 percentage point, whichever comes first. Supermajor relative-price gaps overshoot, so the XOM-CVX spread tends to mean-revert as sector flows rotate between the two large-cap energy names.
The key numbers
The charts
The takeaway
The strategy returned +25.08% on $100,000 starting capital across 31 closed trades with a 61% win rate. Over the same window SPY buy-and-hold returned +68.30%, so the strategy finished trailing the benchmark by 43.22 points. Best single trade +5.20%, worst -4.03%.
The fine print
- Simulated results on historical data — fills, slippage and costs are idealized.
- Past performance does not predict future results.