Sample Pairs

Energy Sector Pairs: XOM/CVX

This case study examines the performance of a statistical arbitrage strategy using Exxon Mobil (XOM) and Chevron (CVX), two major integrated oil and gas companies with similar business models and market exposures.

Fundamental Relationship

  • Both are integrated oil majors with similar business models spanning exploration, production, refining, and retail
  • Shared exposure to global oil and gas prices as primary profit drivers
  • Comparable market capitalization and financial strength profiles
  • Similar dividend policies and capital expenditure patterns
  • Competing operations across the same geographical regions

This fundamental similarity creates a strong economic rationale for their prices to maintain a consistent relationship over time, despite short-term divergences.

Statistical Validation

Our comprehensive statistical analysis confirms the strong relationship between XOM and CVX:

Metric Value Interpretation
Pearson Correlation 0.8532 Strong positive correlation
Correlation Std Dev 0.3195 Moderate variability in correlation
Stability Score -21.9450 Correlation shows some instability

The rolling correlation chart above demonstrates the generally strong relationship between XOM and CVX over time. The 60-day rolling correlation (purple line) and 120-day rolling correlation (orange line) both remain mostly above 0.8, though there are periods of significant drops that contribute to the negative stability score.

While the correlation stability shows some concerns, the cointegration tests provide strong evidence for a tradable relationship:

Cointegration Test Results

Test Statistic Critical Value (5%) p-value Result
ADF Test -2.8878 -2.8654 0.0468 Cointegrated ✓
Johansen Trace 19.3415 15.4943 - Cointegrated ✓

Both tests confirm the presence of cointegration, indicating that while XOM and CVX prices may diverge temporarily, they tend to revert to their long-term equilibrium relationship. The hedge ratio of 0.2015 suggests that for each share of XOM, approximately 0.20 shares of CVX should be traded in the opposite direction to create a market-neutral position.

The spread chart above shows the difference between the two stocks (after applying the hedge ratio), demonstrating the mean-reverting property that is essential for pairs trading. While the spread appears non-stationary at times, our statistical tests confirm it is indeed mean-reverting over the analysis period.

Trading Parameters

Based on our statistical analysis, we established the following trading parameters:

  • Entry Signal: Z-score exceeding +/- 2.0 standard deviations
  • Exit Signal: Z-score returning to +/- 0.5 standard deviations
  • Stop-Loss: Z-score exceeding +/- 3.0 standard deviations
  • Half-Life: 41.97 days (relatively long)
  • Maximum Holding Period: 62 days (1.5× half-life)

Interactive Z-Score Strategy Explorer

The interactive tool below allows you to experiment with different trading parameters and explore how they would affect the signals generated for the XOM/CVX pair. Adjust the thresholds to see how changes in your trading rules would impact potential entry and exit points.

The half-life analysis indicates that while mean reversion does occur, it happens at a relatively slow pace. This suggests a medium-term trading horizon for this pair.

The Z-score chart above shows the normalized spread with our entry and exit thresholds. When the Z-score crosses above +2 or below -2 (red dashed lines), we enter a trade in the direction of mean reversion. The frequent oscillation of the Z-score around these thresholds provides numerous trading opportunities.

Trading Performance

Our backtest of the XOM/CVX pair trading strategy demonstrates impressive results over the test period:

The market value curve above shows the growth of our initial $10,000 capital over the testing period. The steady upward trend demonstrates the consistent profitability of the strategy, reaching over $12,500 by the end of the period.

Blotter

To provide deeper insights into our trading activity, we analyzed the complete trade blotter and ledger results from our backtest:

Timestamp Timestamp.1 XOM Position CVX Position Quantity XOM Entry XOM Exit XOM P&L CVX Entry CVX Exit CVX P&L Total P&L success
2022-07-28 2022-08-03 Short Long 81 $92.64 $91.02 $131.22 $150.39 $155.36 $79.52 $210.74 True
2022-08-23 2022-09-01 Short Long 78 $98.00 $93.87 $322.14 $161.99 $155.54 $-96.75 $225.39 True
2022-09-20 2022-10-03 Long Short 84 $92.44 $91.92 $-43.68 $156.28 $151.73 $72.80 $29.12 True
2022-10-05 2022-11-09 Short Long 79 $99.12 $108.90 $-772.62 $158.53 $177.93 $291.00 $-481.62 False
2022-12-05 2022-12-13 Long Short 70 $106.85 $107.25 $28.00 $176.56 $173.53 $42.42 $70.42 True
2023-01-06 2023-02-02 Short Long 68 $110.53 $111.15 $-42.16 $176.56 $169.01 $-98.15 $-140.31 False
2023-02-10 2023-02-17 Short Long 64 $119.17 $111.28 $504.96 $171.97 $162.85 $-109.44 $395.52 True
2023-03-13 2023-03-21 Long Short 74 $106.54 $107.04 $37.00 $158.71 $159.31 $-8.40 $28.60 True
2023-04-03 2023-05-01 Short Long 68 $116.13 $114.67 $99.28 $169.95 $167.24 $-35.23 $64.05 True
2023-05-02 2023-05-24 Long Short 73 $110.10 $107.59 $-183.23 $160.04 $157.27 $38.78 $-144.45 False
2023-05-31 2023-06-02 Long Short 77 $102.18 $105.76 $275.66 $150.62 $156.26 $-84.60 $191.06 True
2023-06-20 2023-06-26 Long Short 78 $102.72 $104.29 $122.46 $153.68 $154.01 $-4.95 $117.51 True
2023-07-14 2023-07-24 Long Short 80 $100.94 $105.52 $366.40 $153.58 $161.82 $-131.84 $234.56 True
2023-08-09 2023-08-16 Short Long 76 $109.56 $106.34 $244.72 $159.86 $158.63 $-18.45 $226.27 True
2023-09-01 2023-09-21 Short Long 75 $113.52 $114.76 $-93.00 $164.30 $165.19 $13.35 $-79.65 False
2023-09-27 2023-10-02 Short Long 70 $120.20 $115.63 $319.90 $171.04 $166.54 $-63.00 $256.90 True
2023-10-04 2023-10-18 Long Short 77 $111.50 $112.95 $111.65 $163.04 $168.92 $-88.20 $23.45 True
2023-11-08 2023-11-17 Long Short 85 $102.93 $104.96 $172.55 $142.40 $144.46 $-35.02 $137.53 True
2023-12-04 2023-12-18 Long Short 86 $102.43 $101.65 $-67.08 $144.87 $149.68 $-81.77 $-148.85 False
2024-01-16 2024-01-24 Long Short 88 $97.69 $99.60 $168.08 $143.69 $144.92 $-20.91 $147.17 True
2024-01-30 2024-02-02 Short Long 84 $104.85 $101.97 $241.92 $150.12 $152.24 $33.92 $275.84 True
2024-03-01 2024-04-17 Short Long 85 $105.84 $118.63 $-1087.15 $152.81 $156.40 $61.03 $-1026.12 False
2024-04-26 2024-05-15 Long Short 70 $117.96 $118.58 $43.40 $165.89 $163.05 $39.76 $83.16 True
2024-05-23 2024-05-31 Long Short 73 $113.51 $117.26 $273.75 $156.94 $162.30 $-75.04 $198.71 True
2024-06-14 2024-06-24 Long Short 77 $109.11 $114.05 $380.38 $152.57 $159.31 $-101.10 $279.28 True
2024-07-17 2024-07-23 Short Long 74 $117.64 $113.41 $313.02 $161.23 $154.09 $-99.96 $213.06 True
2024-08-08 2024-08-20 Short Long 77 $117.89 $114.58 $254.87 $144.49 $144.69 $3.00 $257.87 True
2024-09-10 2024-09-17 Long Short 83 $110.82 $114.18 $278.88 $138.23 $143.41 $-82.88 $196.00 True
2024-10-01 2024-10-15 Short Long 78 $119.93 $120.35 $-32.76 $149.70 $147.73 $-29.55 $-62.31 False
2024-10-29 2024-11-06 Long Short 80 $117.28 $121.00 $297.60 $148.52 $157.72 $-147.20 $150.40 True
2024-11-26 2024-12-31 Long Short 79 $117.97 $107.57 $-821.60 $162.53 $144.84 $265.35 $-556.25 False
2025-01-10 2025-01-13 Long Short 82 $106.54 $109.29 $225.50 $153.14 $155.35 $-35.36 $190.14 True
2025-01-15 2025-01-22 Short Long 80 $111.51 $109.53 $158.40 $158.33 $156.41 $-30.72 $127.68 True
2025-02-12 2025-02-18 Long Short 84 $107.35 $110.14 $234.36 $154.90 $156.16 $-20.16 $214.20 True
2025-03-05 2025-03-07 Long Short 87 $105.44 $109.02 $311.46 $150.81 $156.34 $-94.01 $217.45 True
2025-03-17 2025-04-03 Short Long 83 $113.76 $112.43 $110.39 $158.72 $156.12 $-41.60 $68.79 True
2025-04-04 2025-04-17 Long Short 91 $104.34 $106.92 $234.78 $143.28 $137.87 $97.38 $332.16 True

Ledger

timestamp XOM Position Qty CVX Position Qty Market Value Daily Return Drawdown Trade Action
2022-07-28 -81 16 10000.00 0.00% 0.00% ENTRY: Short
2022-08-03 -81 16 10210.74 2.76% 0.00% EXIT: $210.74 (PROFIT)
2022-08-23 -78 15 10210.74 0.00% 0.00% ENTRY: Short
2022-09-01 -78 15 10436.13 1.48% 0.00% EXIT: $225.39 (PROFIT)
2022-09-20 84 -16 10436.13 -0.00% 0.00% ENTRY: Long
2022-10-03 84 -16 10465.25 4.15% 0.00% EXIT: $29.12 (PROFIT)
2022-10-05 -79 15 10465.25 0.00% 0.00% ENTRY: Short
2022-11-09 -79 15 9983.63 3.67% -4.60% EXIT: $-481.62 (LOSS)
2022-12-05 70 -14 9983.63 -0.00% -4.60% ENTRY: Long
2022-12-13 70 -14 10054.05 0.64% -3.93% EXIT: $70.42 (PROFIT)
2023-01-06 -68 13 10054.05 0.00% -3.93% ENTRY: Short
2023-02-02 -68 13 9913.74 2.85% -5.27% EXIT: $-140.31 (LOSS)
2023-02-10 -64 12 9913.74 0.00% -5.27% ENTRY: Short
2023-02-17 -64 12 10309.26 3.40% -1.49% EXIT: $395.52 (PROFIT)
2023-03-13 74 -14 10309.26 -0.00% -1.49% ENTRY: Long
2023-03-21 74 -14 10337.86 3.86% -1.22% EXIT: $28.60 (PROFIT)
2023-04-03 -68 13 10337.86 0.00% -1.22% ENTRY: Short
2023-05-01 -68 13 10401.91 2.94% -0.61% EXIT: $64.05 (PROFIT)
2023-05-02 73 -14 10401.91 -0.00% -0.61% ENTRY: Long
2023-05-24 73 -14 10257.46 1.06% -1.99% EXIT: $-144.45 (LOSS)
2023-05-31 77 -15 10257.46 -0.00% -1.99% ENTRY: Long
2023-06-02 77 -15 10448.52 1.78% -0.16% EXIT: $191.06 (PROFIT)
2023-06-20 78 -15 10448.52 -0.00% -0.16% ENTRY: Long
2023-06-26 78 -15 10566.03 1.49% 0.00% EXIT: $117.51 (PROFIT)
2023-07-14 80 -16 10566.03 -0.00% 0.00% ENTRY: Long
2023-07-24 80 -16 10800.59 1.17% 0.00% EXIT: $234.56 (PROFIT)
2023-08-09 -76 15 10800.59 0.00% 0.00% ENTRY: Short
2023-08-16 -76 15 11026.86 1.61% 0.00% EXIT: $226.27 (PROFIT)
2023-09-01 -75 15 11026.86 0.00% 0.00% ENTRY: Short
2023-09-21 -75 15 10947.21 1.23% -0.72% EXIT: $-79.65 (LOSS)
2023-09-27 -70 14 10947.21 0.00% -0.72% ENTRY: Short
2023-10-02 -70 14 11204.11 1.41% 0.00% EXIT: $256.90 (PROFIT)
2023-10-04 77 -15 11204.11 -0.00% 0.00% ENTRY: Long
2023-10-18 77 -15 11227.56 1.24% 0.00% EXIT: $23.45 (PROFIT)
2023-11-08 85 -17 11227.56 -0.00% 0.00% ENTRY: Long
2023-11-17 85 -17 11365.09 2.06% 0.00% EXIT: $137.53 (PROFIT)
2023-12-04 86 -17 11365.09 0.00% 0.00% ENTRY: Long
2023-12-18 86 -17 11216.24 0.70% -1.31% EXIT: $-148.85 (LOSS)
2024-01-16 88 -17 11216.24 -0.00% -1.31% ENTRY: Long
2024-01-24 88 -17 11363.41 1.32% -0.01% EXIT: $147.17 (PROFIT)
2024-01-30 -84 16 11363.41 0.00% -0.01% ENTRY: Short
2024-02-02 -84 16 11639.25 1.00% 0.00% EXIT: $275.84 (PROFIT)
2024-03-01 -85 17 11639.25 0.00% 0.00% ENTRY: Short
2024-04-17 -85 17 10613.13 0.07% -8.82% EXIT: $-1026.12 (LOSS)
2024-04-26 70 -14 10613.13 0.00% -8.82% ENTRY: Long
2024-05-15 70 -14 10696.29 0.84% -8.10% EXIT: $83.16 (PROFIT)
2024-05-23 73 -14 10696.29 -0.00% -8.10% ENTRY: Long
2024-05-31 73 -14 10895.00 2.35% -6.39% EXIT: $198.71 (PROFIT)
2024-06-14 77 -15 10895.00 -0.00% -6.39% ENTRY: Long
2024-06-24 77 -15 11174.28 2.45% -3.99% EXIT: $279.28 (PROFIT)
2024-07-17 -74 14 11174.28 0.00% -3.99% ENTRY: Short
2024-07-23 -74 14 11387.34 1.24% -2.16% EXIT: $213.06 (PROFIT)
2024-08-08 -77 15 11387.34 0.00% -2.16% ENTRY: Short
2024-08-20 -77 15 11645.21 3.04% 0.00% EXIT: $257.87 (PROFIT)
2024-09-10 83 -16 11645.21 -0.00% 0.00% ENTRY: Long
2024-09-17 83 -16 11841.21 1.12% 0.00% EXIT: $196.00 (PROFIT)
2024-10-01 -78 15 11841.21 0.00% 0.00% ENTRY: Short
2024-10-15 -78 15 11778.90 2.47% -0.53% EXIT: $-62.31 (LOSS)
2024-10-29 80 -16 11778.90 -0.00% -0.53% ENTRY: Long
2024-11-06 80 -16 11929.30 1.15% 0.00% EXIT: $150.40 (PROFIT)
2024-11-26 79 -15 11929.30 0.00% 0.00% ENTRY: Long
2024-12-31 79 -15 11373.05 1.46% -4.66% EXIT: $-556.25 (LOSS)
2025-01-10 82 -16 11373.05 0.00% -4.66% ENTRY: Long
2025-01-13 82 -16 11563.19 2.29% -3.07% EXIT: $190.14 (PROFIT)
2025-01-15 -80 16 11563.19 0.00% -3.07% ENTRY: Short
2025-01-22 -80 16 11690.87 1.51% -2.00% EXIT: $127.68 (PROFIT)
2025-02-12 84 -16 11690.87 -0.00% -2.00% ENTRY: Long
2025-02-18 84 -16 11905.07 1.65% -0.20% EXIT: $214.20 (PROFIT)
2025-03-05 87 -17 11905.07 -0.00% -0.20% ENTRY: Long
2025-03-07 87 -17 12122.52 0.85% 0.00% EXIT: $217.45 (PROFIT)
2025-03-17 -83 16 12122.52 0.00% 0.00% ENTRY: Short
2025-04-03 -83 16 12191.31 4.01% 0.00% EXIT: $68.79 (PROFIT)
2025-04-04 91 -18 12191.31 -0.00% 0.00% ENTRY: Long
2025-04-17 91 -18 12523.47 2.25% 0.00% EXIT: $332.16 (PROFIT)

The ledger results track daily equity changes and performance throughout the backtest period. This confirms the strategy’s stability across various market conditions, with strong results during periods of heightened volatility.

Key observations:

  1. Position Management: Consistent implementation of the hedge ratio maintained market neutrality.

  2. Holding Periods: Average holding period of 12.84 days, shorter than our calculated half-life (41.97 days).

  3. Equity Growth: Steady equity progression with manageable drawdowns, confirming the strategy’s robust risk-return profile.

Key Performance Metrics

Profitability

  • Total Profit: $2523.47
  • Average Profit per Trade: $68.20
  • Profit Factor: 1.96

Trade Statistics

  • Win Rate: 78.38%
  • Average Win: $178.04
  • Average Loss: $-329.94
  • Average Holding Period: 12.84 days

Risk Metrics

  • Volatility (annualized): 14.43%
  • Maximum Drawdown: -8.82%
  • Sharpe Ratio: 0.77
  • Sortino Ratio: 0.85

Overall Result

  • Initial Capital: $10,000
  • Final Equity: $12,523.47
  • Alpha (annualized): 0.1071
  • Beta: 0.0337
  • Geometric Mean Return (CAGR): 7.84%

The drawdown chart above shows the percentage decline from peak equity values throughout the testing period. The maximum drawdown of 8.82% is moderate and reflects the strategy’s effective risk management, especially considering the volatile nature of energy stocks.

Strategy Insights

Several key observations emerge from our trading results:

  1. High Win Rate: The 78.38% win rate confirms the strong mean-reversion tendency between XOM and CVX, validating our statistical approach.

  2. Asymmetric Risk-Reward: While average losses ($-329.94) are larger than average wins ($178.04), the high win rate more than compensates, resulting in a strong profit factor of 1.96.

  3. Reasonable Drawdowns: The maximum drawdown of 8.82% is well within acceptable limits for a market-neutral strategy, indicating effective risk management.

  4. Efficient Holding Period: Despite the relatively long half-life estimate (41.97 days), actual trades averaged just 12.84 days, suggesting that mean reversion often occurs faster than the statistical estimate.

  5. Risk-Adjusted Performance: The Sharpe ratio (0.77) and particularly the Sortino ratio (0.85) demonstrate good risk-adjusted returns, with especially strong performance during downside market moves.

Challenges and Considerations

While the overall performance is strong, several factors warrant attention:

  1. Correlation Stability: The negative stability score (-21.9450) indicates significant variations in the correlation between XOM and CVX over time, which could introduce periods of strategy underperformance.

  2. Long Half-Life: The relatively long statistical half-life (42.41 days) suggests that some divergences might persist for extended periods, requiring patience and strong risk management.

  3. VIX Adjustment: The strategy was implemented without VIX-based volatility adjustments. Incorporating market volatility indicators could potentially enhance performance by adjusting position sizing during high-volatility periods.

  4. Market Regime Sensitivity: Energy stocks can be subject to distinct market regimes (contango vs. backwardation in oil futures, for example) which may temporarily affect the pair relationship.

Conclusion

The XOM/CVX pair demonstrates strong characteristics for statistical arbitrage trading, with solid statistical validation and impressive backtest performance. The high win rate, favorable profit factor, and moderate drawdowns all suggest this pair offers a compelling opportunity for market-neutral trading.

Despite some concerns regarding correlation stability and the relatively long half-life, the actual trading results show that the strategy effectively captures profits from temporary price divergences while maintaining low correlation to broader market movements.

Based on these results, the XOM/CVX pair represents a prime example of statistical arbitrage potential in the energy sector, offering both strong returns and diversification benefits within a broader investment portfolio.

Implementation Recommendation

For optimal implementation, we recommend:

  1. Using the established hedge ratio of 0.2010 to maintain market neutrality
  2. Monitoring correlation stability and adjusting position sizing accordingly
  3. Implementing a trailing stop-loss strategy during periods of extended divergence
  4. Considering additional filters based on energy sector fundamentals