Direct Answer
Rolling drawdown is a running measure of how far a value has fallen from its most recent peak, recalculated continuously as new data arrives. It's calculated as Rolling Drawdown (%) = (Current Value − Rolling Maximum so far) / Rolling Maximum so far × 100, and the result is always zero or negative. Unlike a single "maximum drawdown" backtest statistic, it's a continuously updating series that shows how deep and how long each drawdown period lasted.
Key Takeaways
- Rolling Drawdown (%) = (Current Value − Rolling Maximum so far) / Rolling Maximum so far × 100, the result is always zero or negative.
- It's a continuously recalculated series, not a single backtest number: a "maximum drawdown" statistic is just the deepest point that series ever reaches.
- The rolling maximum only moves upward, at a new peak, it never resets down mid-series, which is what keeps the running comparison anchored to the most recent high.
What Is Rolling Drawdown?
Rolling drawdown tracks the ongoing gap between a value, a portfolio balance, an equity curve, an asset's price, and the highest value that series has reached so far. As new data comes in, the series keeps a running "high water mark," the rolling maximum, and compares every new reading back to it. When the current value sits at a new high, rolling drawdown reads zero. Any time the current value sits below that high, rolling drawdown reads negative, and it stays negative until the series recovers back to a new peak.
Because it recalculates continuously rather than reporting one summary figure, rolling drawdown produces a full series that can be charted alongside price or portfolio value, making it possible to see not just how deep a decline got, but how long it lasted and how often shallower declines occurred in between.
The Formula
Rolling Drawdown (%) = (Current Value − Rolling Maximum so far) / Rolling Maximum so far × 100
The "rolling maximum so far" is simply the highest value the series has recorded up to and including the current point, it updates upward whenever a new high is made and otherwise stays fixed while the current value moves below it. Because the current value can never exceed the rolling maximum by definition (the rolling maximum is set to match it at every new high), the numerator is always zero or negative, and so is the result.
Worked Example
A portfolio peaks at $110,000, then falls to $95,000.
Rolling Drawdown = (95,000 − 110,000) / 110,000 × 100 = -13.6%
The $110,000 peak becomes the rolling maximum the moment it's reached. As the portfolio value drops to $95,000, every subsequent reading is compared back to that same $110,000 high water mark until a new peak above $110,000 is eventually made, at which point the rolling maximum resets upward and the drawdown calculation starts measuring from the new high instead.
How Rolling Drawdown Is Used
Assessing risk actually experienced
Because it's a full series rather than one number, rolling drawdown is commonly reviewed to see how often and how deeply a portfolio or strategy has pulled back from its highs over time, not just the single worst instance.
Comparing drawdown duration, not just depth
Two strategies can share the same maximum drawdown figure yet look very different on a rolling drawdown chart, one might spend most of its time near zero with one sharp dip, while another sits meaningfully underwater for extended stretches. Traders commonly use the rolling series to distinguish those two patterns.
Setting risk-management thresholds
Some traders and fund managers use rolling drawdown as an ongoing monitoring signal, for example, reviewing exposure or position sizing when the running drawdown crosses a threshold they've set in advance, though the specific threshold and response vary by strategy and are not a standardized rule.
Limitations
- It's lagging by construction, rolling drawdown can only be measured against a peak that already occurred, so it confirms and quantifies a decline already underway rather than warning of one in advance.
- It says nothing about cause, a deep rolling drawdown reads the same whether it came from broad market conditions, a single concentrated position, or elevated volatility; the number alone doesn't explain why the decline happened.
- Time window matters, a rolling drawdown series calculated over a short window versus the full history of a portfolio can tell different stories, since the rolling maximum used as the reference point depends on how far back the calculation looks.
Common Mistakes
- Treating a single "maximum drawdown" headline number as the full picture, it's just the single deepest point the rolling drawdown series ever reached; it doesn't show how long the portfolio stayed underwater or how frequently smaller drawdowns occurred.
- Comparing rolling drawdown figures across different time windows, a portfolio's rolling drawdown calculated over the last month and the same portfolio's rolling drawdown calculated since inception are answering different questions, since each is measured against a different rolling maximum.
- Assuming a return to zero drawdown means the underlying risk is gone, a rolling drawdown reading of zero only means the current value matches its prior high; it says nothing about how quickly a new decline could begin from there.
The Measure That Describes the Experience of Holding
Rolling drawdown tracks the distance from the running peak, which makes it the closest quantitative match to what holding an asset actually feels like. Returns describe the outcome; drawdown describes the path, and the path is what determines whether a position gets held to the outcome.
Use it to set position size rather than to evaluate performance. Looking at the worst drawdown an asset or strategy has produced, and asking whether you would have continued through it at your intended size, is a more realistic test than any return figure. If the answer is no, the size is wrong now.
The mistake is reading the historical maximum as a bound. Every worst drawdown was set by conditions that had not previously occurred, and a longer history generally reveals deeper ones. Treating the observed maximum as a limit is treating a sample as a distribution.
The measure also depends on the period examined. A drawdown chart starting after a major decline shows a much gentler history than one including it, and comparisons between assets are only meaningful over identical windows that cover comparable conditions.
Rolling Drawdown FAQs
What is rolling drawdown?
Rolling drawdown is a running measure of how far a value has fallen from its most recent peak, recalculated continuously as new prices or balances come in. It's expressed as Rolling Drawdown (%) = (Current Value − Rolling Maximum so far) / Rolling Maximum so far × 100, and it's zero or negative, it never goes positive.
How is rolling drawdown different from maximum drawdown?
Maximum drawdown is a single backtest statistic, the worst peak-to-trough decline over a period, reported as one number. Rolling drawdown is a continuously updating series that shows how deep and how long every drawdown period lasted, not just the single worst one.
What does a rolling drawdown of -13.6% mean?
It means the current value sits 13.6% below the highest value reached so far in the rolling window. For example, a portfolio that peaked at $110,000 and has since fallen to $95,000 has a rolling drawdown of (95,000 − 110,000) / 110,000 × 100 = -13.6%.
Can rolling drawdown be positive?
No. Rolling drawdown is zero or negative by definition. It reads zero at a new peak, since the current value equals the rolling maximum, and turns negative any time the current value sits below that peak.
How often is rolling drawdown recalculated?
It updates with every new data point in the series, each new price, bar, or balance check compares the current value to the highest value observed so far and recalculates the percentage. The rolling maximum only moves up, at a new peak; it never resets downward mid-series.
Is rolling drawdown a leading or lagging measure?
Lagging. It can only compare the current value to a peak that already happened, so it confirms and quantifies a decline already underway rather than predicting one before it starts.
How does the choice of window affect what a rolling drawdown shows?
The window determines which peak the current value is measured against, so a short window measures the decline from a recent high while a long one measures against a distant peak that may never be revisited. Both are legitimate questions. A portfolio can show a small drawdown on a short window while remaining far below a peak that a longer window would still reference.
Should drawdown be measured on closing values or on intraday extremes?
Closing values produce a smoother series and understate the worst point actually experienced. Intraday extremes capture the maximum stress but include moves that were never realised and that a holder may not have seen. For risk limits that trigger action, closing values are usually more practical, while intraday extremes better describe what a stop-based strategy would have experienced.
How does drawdown behave differently for a portfolio than for a single asset?
Portfolio drawdown reflects the combined path, which can be shallower than any individual holding's if the components decline at different times, or as deep as the worst holding if they decline together. This is why portfolio-level drawdown is the figure that matters for risk limits, and why measuring it only on individual positions systematically understates the exposure during correlated declines.