Maximum Adverse Excursion (MAE) is the largest unrealized movement against a trade while it is open, while Maximum Favorable Excursion (MFE) is the largest unrealized movement in the trade's favour before exit. They are intratrade path measures, not account-level drawdown statistics.
Measure excursion from the trade entry
For a long position, adverse excursion is the movement from entry down to the lowest relevant price reached while the trade remains open; favourable excursion is the movement from entry up to the highest relevant price. For a short position, the favourable and adverse directions reverse.
The result can be expressed in price units, currency, percentage return or normalized risk units such as R.
Final P&L hides the path
A trade that closes at +1R may first have moved −0.8R and later +2.5R. Another +1R trade may never have moved more than −0.1R against the position. Final P&L treats them equally even though their paths were very different.
MAE and MFE preserve that missing information.
MAE can reveal stop-placement questions
If many valid winning trades routinely experience a certain adverse excursion before becoming profitable, that pattern can motivate research into whether stops are too tight. If large MAE is concentrated in losers, it may indicate that earlier invalidation deserves testing.
This is a research question, not permission to move a stop on a live trade. Stop-Loss Risk owns the precommitted risk and execution problem.
MFE can reveal exit questions
If trades frequently achieve a large favourable excursion but close with much smaller realized gains, review whether the exit rule is giving back more of the move than intended. If large MFE occurs only in rare outliers, a tighter exit could also destroy the strategy's positive skew.
The distribution matters more than one memorable trade.
Data resolution changes the measurement
Tick data, one-minute bars and hourly bars do not preserve the same path detail. Coarse bars can show a high and low without proving which occurred first within the bar.
For strategies whose stop and target could both be touched inside one bar, the sequence assumption can materially change MAE/MFE and backtest interpretation.
Include position direction and scaling rules
Partial entries, scale-outs and moving size complicate excursion measurement. Decide whether the analysis is based on the original entry, volume-weighted entry, full-position mark-to-market P&L or another explicit convention.
Do not compare excursion values produced by different definitions as if they were identical.
Do not optimize stops and targets directly on one sample
It is tempting to choose the stop just beyond the largest MAE of historical winners or the target near the most common MFE. That can overfit the exact sample.
Any stop/exit change derived from excursion analysis should be tested out of sample and across relevant market conditions through Strategy Validation.
MAE/MFE is not maximum drawdown
Maximum Drawdown measures the worst peak-to-trough decline in an account or strategy equity path. MAE and MFE measure movement from one trade's entry while that trade is open.
The word “maximum” appears in both, but the entity and reference point are different.
Use excursions with the journal
Store MAE and MFE beside setup, risk, final outcome and exit reason in the Trading Journal. Then review distributions by setup, market and regime only where the sample is large enough to support the comparison.
MAE and MFE are useful because they show what happened between entry and exit. They are evidence for stop and exit research, not mechanical instructions to widen risk or harvest every historical excursion.