Trading Drawdowns and Recovery Maths: Protect the Ability to Continue
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Executive Summary
- ✦Measure drawdown from the latest equity peak.
- ✦Recovery percentages rise faster as losses deepen.
- ✦Fixed-fractional sizing reduces cash risk with equity.
- ✦Define review and size-reduction thresholds before a drawdown.
Trading Drawdowns and Recovery Maths: Protect the Ability to Continue
Learning objective: calculate drawdown correctly, understand why recovery requires a larger percentage gain, and use that relationship when setting trading risk.
A drawdown measures the decline from an account's previous peak to a later trough. It is not the same as the loss on one trade. Drawdown combines the size and sequence of losses and shows how far capital has moved away from its high-water mark.
The mathematics is asymmetric: losing 20% and then gaining 20% does not return an account to its starting value.
1. Measure drawdown from the peak
Use:
Drawdown = (peak equity − current equity) ÷ peak equity × 100
If an account peaks at £20,000 and falls to £17,000, the drawdown is £3,000, or 15%. Keep the peak fixed until a new high is made. Calculating each loss from a shrinking recent balance understates the total decline.
Track both closed-equity drawdown and, where relevant, mark-to-market equity including open positions. The latter can reveal risk that a closed-trade report hides.
2. Calculate the required recovery
Use:
Required gain = drawdown ÷ (1 − drawdown)
Write drawdown as a decimal. A 20% drawdown requires a 25% gain from the lower balance to recover. A 50% drawdown requires 100%. As losses deepen, recovery effort rises faster.
| Drawdown | Gain needed to recover |
|---|---|
| 5% | 5.3% |
| 10% | 11.1% |
| 20% | 25.0% |
| 30% | 42.9% |
| 50% | 100.0% |
3. Connect drawdown to position risk
Position-risk percentages are examples, not universal rules. Their effect depends on win rate, payoff distribution, correlation, gaps and losing streaks.
With fixed-fractional sizing, cash risk falls as equity falls, which can slow further losses. It also means recovery is based on a smaller position base. Increasing risk to “win it back” can accelerate both recovery and ruin; it changes the strategy precisely when decision quality may be under pressure.
4. Define a drawdown response before it occurs
A plan can include review thresholds, size reductions, a pause after process violations, and a test for whether market conditions still match the strategy. A drawdown alone does not prove a strategy has failed. Compare its depth and duration with tested expectations, allowing for the limits of the sample.
Do not change rules merely because several valid losses arrived together. Do investigate execution drift, hidden correlation, unusual slippage or a broken assumption.
Worked example
A hypothetical account begins at £30,000. After a series of trades it reaches £31,500, then falls to £26,775.
- Peak-to-trough loss: £4,725.
- Drawdown: £4,725 ÷ £31,500 = 15%.
- Recovery needed: 0.15 ÷ 0.85 = 17.65% from £26,775.
A 15% gain from the trough would produce about £30,791, still below the £31,500 peak. This is why equal loss and gain percentages do not cancel.
Suppose the strategy normally risks 1% of current equity per trade. Cash risk was £315 at the peak and becomes £267.75 at the trough. That may reduce the speed of further decline, but it also requires patience during recovery. The 1% is illustrative; an appropriate amount must come from tested performance, liquidity and personal loss capacity.
Common mistakes
- Measuring from the starting deposit instead of the latest peak.
- Ignoring open-position losses.
- Assuming a 20% gain repairs a 20% loss.
- Increasing leverage emotionally after a losing streak.
- Treating a backtest's maximum drawdown as a guaranteed limit.
- Ignoring correlated positions that create one large portfolio loss.
- Evaluating only depth and not how long recovery takes.
Practical checklist
- What are the current equity peak and drawdown?
- Does the figure include open positions and realistic costs?
- What gain is mathematically required for recovery?
- Is the drawdown within tested expectations?
- Were rules followed on the losing trades?
- Has correlation or market regime changed?
- Which review and size-reduction thresholds were predefined?
- Can the strategy continue without forcing trades?
The Money Man view
Survival is a trading constraint, not a slogan. Risk should be small enough that a normal losing sequence leaves the trader able to execute the strategy consistently. The analysis is invalid if it treats historical maximum drawdown as a hard future floor or assumes recovery will occur on schedule.
This tutorial is educational information prepared with AI-assisted research and writing. It is not personalised financial advice or a promise of recovery. Trading can cause substantial or total loss.