最大回撤

What is Maximum Drawdown in forex and 差價合約（CFD）交易

Maximum Drawdown (MDD) is the largest observed decline in a trading account’s equity from its absolute peak value to its subsequent lowest value, before a new equity peak is achieved. It is expressed as a percentage and is the primary measure of downside risk and capital preservation effectiveness for a trading strategy over a specific period. A low Maximum Drawdown is essential; it indicates better risk management and a lower capital requirement for recovery, directly impacting the trader’s mental capital and long-term viability. Traders verify their Maximum Drawdown using detailed performance reports generated by their trading platform’s strategy tester or live account history, such as the reports available in MetaTrader 4 (MT4) or MetaTrader 5 (MT5), and can explore other trading terms here.

Key facts about Maximum Drawdown

• Definition: The single largest historical loss from a peak equity value to a subsequent trough equity value.
• Measurement Unit: Always expressed as a percentage loss from the peak; can also be tracked in currency terms.
• Formula Variables: Requires Peak Value (P_peak) and the corresponding Trough Value (T_trough) occurring before the next peak.
• Purpose: The standard benchmark for comparing the downside risk and capital preservation quality of different trading systems.
• Recovery Requirement: A Maximum Drawdown of 50% necessitates a subsequent 100% gain just to return to the break-even peak equity level.
• Proprietary Trading: Often used as a strict breach limit by prop firms; typical trailing limits range from 5% to 10%.

How Maximum Drawdown works in forex and CFD trading

Maximum Drawdown measures the worst-case scenario loss that an account equity experiences during a test period or live trading history.

計算步驟如下：

1. Identify the Equity Time Series: Record the account’s Equity value at regular intervals, typically after every trade closure, or dynamically in real-time.
2. Determine the Running Peak: Track the highest historical Equity value achieved up to the current point, P_running.
3. Calculate Current Drawdown: At any point, the current drawdown in percentage terms is calculated as: DD_% = ((E_current – P_running) / P_running) × 100
   where E_current is the current Equity value.
4. Identify the Maximum Drawdown: The Maximum Drawdown (MDD) is the lowest (most negative) value recorded for the DD_% over the entire analysis period. MDD = min((E_current – P_running) / P_running) × 100

The MDD is the largest distance between any peak and the following trough. The process stops checking the initial peak once a new higher peak is reached, starting the peak-to-trough measurement again.

Example of Maximum Drawdown with a real trade

A trader begins with an initial balance of $10,000.

Trade Sequence: The account equity follows a series of up and down movements.

Result: The Maximum Drawdown is -25.0%, which occurred when the equity dropped to $9,750 from the $13,000 peak.

How Maximum Drawdown affects your cost and risk

Maximum Drawdown is a pure risk metric; it does not affect execution cost, but it fundamentally quantifies strategy risk and determines the psychological and financial buffer required for a trader. A high Maximum Drawdown forces a strategy to generate disproportionately higher returns to recover, increasing the risk required for subsequent trades.

Maximum Drawdown compared with related concepts

Maximum Drawdown vs. Daily Drawdown

Maximum Drawdown is the largest peak-to-trough decline over the entire trading history of the account or strategy, whereas Daily 回撤 is the maximum permissible or realized loss in equity or balance within a single 24-hour period, focusing on short-term risk control.

Maximum Drawdown vs. Relative Drawdown

Maximum Drawdown refers to the single largest peak-to-trough decline observed over an analyst’s specified evaluation period, thus being an absolute worst-case historical loss, whereas Relative Drawdown refers to the peak-to-trough decline that occurred at any specific point in time, simply measuring the loss relative to the immediate preceding peak.

Broker differences in Maximum Drawdown across the industry

Brokers do not typically have a formal “Maximum Drawdown” policy for standard retail accounts, as it is a client-side performance metric, but their execution model impacts the outcome. Prop trading firms, however, strictly enforce Maximum Drawdown limits.

How to verify Maximum Drawdown on your trading platform

To verify your historical Maximum Drawdown using MetaTrader 4 (MT4) or MetaTrader 5 (MT5), follow these steps:

1. Open Terminal/Toolbox: In MT4, press Ctrl+T to open the Terminal window; in MT5, open the Toolbox window.
2. Navigate to Account History: Click on the Account History tab in the Terminal/Toolbox window.
3. Generate Report: Right-click anywhere in the history area and select Save as Detailed Report (MT4) or Save Report (MT5).
4. Open the Report File: The platform will generate an HTML file; open this file in your web browser.
5. Locate the MDD Metric: Scroll down to the Drawdown section of the report.
6. Check Maximum Drawdown: The report explicitly lists Maximum Drawdown as a percentage value, such as 15.4% or 8.2%. The number should reflect the largest single drop in your account equity from an all-time high.