Why MDD matters — looking at maximum drawdown directly

When you start investing, the return number grabs your eye first. How many percent each year, how many years to double the money. There's another number worth looking at first, though. MDD — maximum drawdown — shows how deep the account fell from its high during a market dip. Here's why that number carries more weight than it first looks.

What MDD means

MDD stands for Maximum Drawdown. In one line, it answers "during that period, how far did the asset fall from its peak."

For example, an asset starts at $100,000, rises to $150,000, then falls to $105,000 before recovering. The MDD for that span is -30% from the peak of $150,000. Even if the asset finishes the period at $200,000, the MDD number stays at -30%.

It's the number that tells you, separately from the final result, how deep the dip went along the way.

Why it matters

A return chart looks calm because it ends higher. From inside the curve, each deep dip is a scary moment.

Think of a roller coaster. The start and the end are at similar heights — "the ride ended up about where it began." But during the deep dip, your stomach drops. The account does the same thing. Even when the chart finishes higher, going through a -30% or -40% valley along the way is when you feel like closing the app and walking away.

So the scary thing isn't the MDD number itself. The scary thing is that if you can't ride through the valley, you don't get to ride the recovery.

How -30% MDD actually feels

A number like -30% sounds abstract until you convert it. With $100,000 invested, -30% MDD means at one point the balance reads $70,000. With $50,000, that moment reads $35,000.

The MDD window isn't quick either. From the bottom, climbing back to the previous high can take 3 to 5 years. During that span, every glance at the balance is a flashing reminder.

That's why "the MDD I can hold through" is the line that gets drawn first. If you know you can only absorb -20%, building a portfolio with assets that historically post -40% MDD doesn't fit your own line.

How to read MDD

Two things to look at alongside MDD.

A CAGR of 12% with a -50% MDD isn't an attractive curve once you look at both. A CAGR of 8% with a -15% MDD is a steadier curve, even with the lower headline number. Reading one number alone misses the shape.

The MDD you can absorb is something to set honestly. If -10% costs you sleep, that's your line. If you can keep adding to a position at -40%, that's your line. The reference point is yours — not someone else's.

Holding both numbers together makes it easier to pick assets, and easier to set weights, without flinching.

Looking at it directly

Running the asset against past data is the fastest way to see it. The MDD number and the curve shape come out together for that asset. Not just the number — the actual depth and length of the valley.

The point where the MDD was deepest, and how long it took the curve to climb back to the previous peak — looking at those two together is the most honest test of whether you'd really have held through it.

One thing worth keeping in mind

The results are simulations built from past market data. Real accounts include trading fees, taxes, and slippage (small differences in execution price), which aren't reflected here. Under the same conditions, the actual return can come out lower than the displayed value.

The bigger point is that past MDD doesn't guarantee future MDD. The next 10 years can bring a deeper valley or a shallower one. The number itself is reference. The depth you can hold through is something you set yourself.

• This information is not investment advice.
• Past performance does not guarantee future results.
• Backtest results are simulations and may differ from actual trading outcomes.