Level 9 · Lesson 2 of 16 · 6 min read
Edge Decay: Why Strategies Stop Working
Markets change. What worked three years ago may not work today. Adaptation is the only constant.
Researched and written by Laurent Why Edges Disappear
Three forces cause edge decay:
- Regime change: A strategy designed for trending markets fails when the market shifts to a range. A mean-reversion strategy built during low-volatility years fails when volatility spikes.
- Crowding: When enough traders discover and use the same edge, the pattern changes. If everyone buys at the 61.8% Fibonacci retracement, market makers front-run it, and the level stops working as cleanly.
- Structural change: New regulations, algorithmic trading evolution, changes in market microstructure. Today's forex market is not the same as it was a decade ago.
How to Detect It
Track these metrics monthly:
- Win rate: Is it declining consistently over 3+ months?
- Average RR: Are your winners getting smaller relative to losers?
- Expectancy: Has it dropped below +0.10R consistently?
- Max drawdown: Is the current drawdown exceeding backtest maximums?
If multiple metrics are degrading simultaneously over 50+ trades, the edge may be decaying. If it's just a rough month with normal metrics, it's probably variance, not decay.
The response: If edge decay is confirmed, reduce position sizes (halve your risk) while you investigate. Don't abandon the strategy entirely until you've determined whether it's a temporary market regime mismatch or permanent decay.
Key Takeaways
- • Market regimes change: trending becomes ranging, volatile becomes quiet.
- • Crowding: when too many traders use the same strategy, the edge disappears.
- • Monthly strategy reviews with key metrics catch decay before it becomes fatal.
- • The ability to build and test new strategies is more valuable than any single strategy.