Maximum Adverse Excursion (MAE) and Maximum Favorable Excursion (MFE) Analysis

• Developed by quantitative analyst John Sweeney, MAE and MFE are the ultimate mathematical diagnostic tools for trading systems. • Maximum Adverse Excursion (MAE) measures the largest unrealized drawdown experienced while in an open trade. • Maximum Favorable Excursion (MFE) measures the largest unrealized profit peak reached before trade termination. • MAE analysis exposes the exact cluster boundary where losing trades can be abandoned without prematurely killing winning trades. • MFE analysis reveals whether your profit targets are consistently leaving massive money on the table or if targets are set unrealistically far.

When a trade is executed, price rarely shoots in a straight line directly to Take Profit without moving against you. Understanding MAE: Imagine you enter a long position on Bitcoin at $64,000 with a stop loss at $63,000 ($1,000 risk = 1.0R). Price pulls back to $63,600 before rallying to hit your target at $66,000 (+2.0R). • In this winning trade, the deepest unrealized loss was $400 ($64,000 - $63,600). • Therefore, MAE for this trade was 0.40R. If you plot the MAE of 100 backtested trades on a scatter plot: • You observe that 92% of your winning trades have an MAE of 0.45R or less. • In other words, winning trades almost NEVER pull back more than halfway to your stop loss! • Conclusion: Your 1.0R stop loss is needlessly wide! By tightening your stop loss from $1,000 to $550 (0.55R), your position size doubles, and your 1:2.0 trade transforms into an institutional 1:3.64 R:R winner. Understanding MFE: Similarly, if your winning trades consistently hit an MFE of 5.5R, but your journal shows you routinely exit at 2.0R, MFE analysis proves you are prematurely suffocating your winners.

Step-by-Step MAE / MFE Backtesting Protocol: 1. Add MAE and MFE Columns to Your Backtesting Sheet: - For every trade executed in the Bar Replay terminal, log: - Entry Price, Stop Loss Price, Planned Target. - Lowest Price reached during trade life (for Longs). - Highest Price reached during trade life (for Longs). 2. Calculate Normalized R-Excursions: $$\text{MAE (R)} = \frac{|\text{Entry Price} - \text{Worst Price During Trade}|}{\text{Planned Stop Distance}}$$ $$\text{MFE (R)} = \frac{|\text{Entry Price} - \text{Best Price During Trade}|}{\text{Planned Stop Distance}}$$ 3. Plot the MAE Scatter Plot: - Plot MAE on the X-axis (from 0.0R to 1.0R) against Realized Outcome (Win vs Loss) on the Y-axis. - Locate the "Separation Threshold"—the MAE value beyond which winning trades virtually cease to exist. 4. Calibrate Optimized Parameters: - Set your new stop loss distance at the Separation Threshold + 10% volatility buffer.

Common Mistakes: • Over-Fitting Stop Distance: Setting your stop at the exact lowest MAE tick of a past winning trade. You must allow a statistical buffer for market regime shifts. • Ignoring Liquidity Sweeps: Tightening stops based on MAE without checking whether structural liquidity rests just below. Structural invalidation must always take precedence over pure mathematical curve fitting. Institutional Best Practices: • Separate Trending vs Ranging MAE: Calculate MAE separately for high-momentum London breakout setups versus Asian range mean-reversion setups. • Exit Efficiency Metric: Calculate $\text{Exit Efficiency} = \text{Realized R} / \text{MFE}$. Institutional traders target an Exit Efficiency $>70\%$.

Primary Metric to Track: Trade Harvest Ratio ($THR$) $$THR = \frac{\text{Average Realized R of Winning Trades}}{\text{Average MFE of Winning Trades}}$$ Benchmark: • $THR > 0.75$: Exceptional profit capture. • $THR < 0.50$: Serious profit-taking leak; you are giving back more than half of your trade's peak potential before closing.