How this instrument works
Maximum drawdown measures the single worst decline a portfolio actually lived through — the percentage drop from its highest recorded value (the peak) to its lowest point afterward (the trough), before it climbed to a new high. Unlike volatility, which averages how much returns bounce around a mean in both directions, MDD reports only one number: the deepest hole an investor would have sat in had they held from the top straight through to the bottom. A fund can carry low volatility and still post a brutal MDD if its losses cluster into one sustained slide rather than scattering evenly across many small moves.
The formula divides the dollar loss by the peak, not the trough, because that figure is the reference point the investor actually experienced — it was the balance on the statement the day before the decline began, and every later loss is measured against that high-water mark. Portfolio managers scan an entire return history for the single largest such peak-to-trough gap, not just one pair of points; this instrument computes the one pair you supply, which is exactly how a due-diligence analyst re-checks an MDD figure quoted in a fund's fact sheet.
What the number leaves out matters as much as what it shows. MDD says nothing about how long the trough lasted or how quickly the account recovered — a 35% drawdown that rebounds in four months reads identically to one that never fully recovers. It also depends entirely on the window of history examined; stretch the lookback period and a deeper drawdown can surface, or a shallower one if the worst stretch falls outside the range. That does not make it less useful, only narrower: it is a magnitude measure, not a forecast, a duration, or a probability.
- Enter Peak portfolio value, $ — the highest balance the account reached before it started falling.
- Enter Trough (lowest) portfolio value, $ — the lowest balance it reached before the next new high.
- Read Maximum drawdown, % — the size of that decline, measured against the peak.
- Compare the figure against your own tolerance for loss, or against another fund's MDD over the same stretch of history.
Worked example — the $100,000 portfolio
Peak portfolio value, $100,000. The account later slides to a Trough (lowest) portfolio value of $65,000 before climbing to a new high. MDD = (100,000 − 65,000) ÷ 100,000 × 100 = 35.0. Maximum drawdown, % reads 35.0 — a bit over a third of the account's high-water balance was lost at the worst point of the ride, the single largest decline this investor actually experienced.
Recovering from that 35% drawdown does not take a 35% gain — it takes 53.8%, because the climb back is measured against the smaller $65,000 base, not the original $100,000 peak: $65,000 growing by 53.8% returns to $100,000 exactly. That gap between the loss and the gain needed to erase it is the detail investors most often misjudge, and it widens sharply as the drawdown deepens — a 50% drawdown needs a 100% gain, and a 75% drawdown needs a 300% gain to fully recover.
Questions
What counts as the peak and trough in this calculation?
The peak is the highest portfolio value reached before a decline begins; the trough is the lowest value the account reaches afterward, before it sets a new high. Order matters — the low point must arrive after it in time. If a later value falls even lower without the account ever climbing past that earlier high first, the new low is still part of the same drawdown, not a separate one.
How is maximum drawdown different from volatility or standard deviation?
Standard deviation averages how far returns swing around a mean, counting up moves and down moves together. Maximum drawdown ignores the average entirely and reports only the single worst realized decline — the largest loss an investor would have actually experienced holding from peak to trough. Two portfolios can share identical volatility yet post very different MDDs, because MDD depends on how losing periods are sequenced, not just how large they are on average.
Why does recovering from a drawdown require a bigger percentage gain than the loss itself?
Because the recovery gain is measured against the smaller trough value, not the original peak. A 35% loss leaves 65% of that original value remaining, and climbing back up from that smaller base takes a 53.8% gain (1 ÷ 0.65 − 1). The deeper the drawdown, the more lopsided the math gets: a 50% loss needs a 100% gain, and a 90% loss needs a 900% gain just to break even.
Does maximum drawdown tell me how long the decline lasted?
No — it measures depth, not duration. Two portfolios can post an identical 35% maximum drawdown while one recovers within a single quarter and the other takes five years, or never fully recovers. Analysts who care about that difference track a separate figure, often called drawdown duration or recovery time, alongside the MDD percentage this instrument computes.
Who actually uses maximum drawdown, and for what decision?
Fund due-diligence analysts use it to screen hedge funds, CTAs, and separately managed accounts that post similar average returns but very different worst-case histories. Retail investors and robo-advisor risk questionnaires use a fund's historical MDD as a plainer stand-in for 'how bad could this get' than volatility, since it describes one lived loss rather than a statistical average.
Can maximum drawdown be negative or exceed 100%?
No. It is bounded between 0%, meaning the portfolio never fell below its prior peak, and just under 100%, meaning the value approached zero. It cannot go negative, since a trough can never sit above the peak it followed, and this instrument rejects any trough value entered higher than the peak.
References
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.