On Wall Street, no one ever says “okay, enough is enough.” The mentality is always “if a little bit is good then a lot is better. And if a lot is better then way more is great!” Usually, people have to lose a lot of money before this wears off. And then it starts all over again in some other pocket of the markets.
Josh Brown
Among the core principles during market sell-offs, diversification is supposed to work.
Not every day. Not every drawdown. But over the long run, it should work.
The catch, there’s always a catch, is that if diversification always worked, all the time, it wouldn’t actually be diversification. It’d just be free money. And markets don’t hand out free money. What diversification really does is let you earn more return for a given unit of risk. That’s the deal. That’s the whole deal.
But correlations are slippery. The same two assets can move in completely opposite directions depending on what kind of fire is burning. Normal recession? Stocks down, bonds up. Inflation shock? Stocks down, bonds down too. Dollar as the ultimate safe haven? Sure…until the crisis is being authored by the person who controls the dollar.
Context changes everything.
And here’s the other thing: whatever is working right now will eventually get crowded, leveraged, and pushed to an absurd extreme. It happens to single assets. It happens to strategies. It happens to any combination of assets once enough capital piles in and it becomes mainstream enough to be dangerous.
The same investor who complains about a platform only offering 10 years of backtest data is the same person who panics when their entire screen turns red on a single trading day. They want more history in theory, but they can’t handle a little volatility in practice.
Yes, even the “impossible” combinations happen. Stocks up, volatility up. Or the reverse. The combos that blow up your backtest assumptions show up eventually, because markets are not bound by your model.
Anything can happen. That’s not pessimism. That’s just the deal you agree to when you invest.
Here is a list of instruments I use. Look at 1-day, 1-week,1-month and 3-month returns:
The more you go right, the more you see a mix of green and red. Not that such a picture is much informative, considering I have some products that already mix different assets…but I thought it was a nice idea to show.
Diversification is not a shield against bad days.
It’s not even a shield against bad months. If your portfolio is down 8% and your bonds are down 6%, that’s not diversification failing, that’s just…a Tuesday.
What diversification is actually doing is something quieter and less satisfying to watch in real time. It’s compressing the left tail. It’s reducing the probability that you end up with a genuinely catastrophic outcome. It spreads risk. It doesn’t eliminate it. There’s a difference, and it matters.
So when investors start fretting and laughing about “correlations going to 1”, while the stock market is still within 10% of its all-time high, that’s worth pausing on. Because diversification, as a risk management tool, was never designed to protect you here. This part of the distribution isn’t the problem. A 10% drawdown is noise. The job of diversification is to prevent the 25%, 35%, 40% losses: the ones that derail retirement plans and force people to sell at the worst possible moment.
That this is poorly understood is evidenced by one thing: the commercial success of structured products that offer explicit, but limited, downside protection. The ETF that eats the first 15% of losses but let the owner enjoy the full -40% and counting. The 3-stock certificate that pulls the chair under your ass when one of those three goes into a meltdown. If investors genuinely understood how diversification worked across the full distribution, those products would be a niche curiosity. They’re not.
The most ‘charitable’ explanation is that retail investors think: if it’s not protecting me now, it won’t protect me when things get really bad. The logic feels intuitive. It’s also wrong.
Tail-risk strategies like TAIL need deep drawdowns to pay off. Trend-following strategies need extended, directional moves to fully reverse before they provide protection. The protection exists, at that cost, exactly because it doesn’t show up every quarter.
Just as a reminder: two assets with zero correlation move in the same direction 50% of the time. (The 50% figure assumes symmetric distributions. If both assets have positively skewed returns (more up days than down days, as equities and bonds), they could actually move in the same direction slightly more than 50% of the time even with zero correlation, because “same direction” would most often mean “both up.”)
Uncorrelated is not opposite. It’s just… unrelated. If you’re holding a diversifier expecting it to zig every time your stocks zag, you’ve misunderstood what you own.
Let’s take our naive portfolio:
On an inflation-adjusted basis, it lost money in 8 years out of 34:
Now look at each component:
Diversification matters for two different jobs. Most people only think about one of them.
The first job is wealth preservation. This one feels obvious…until you remember inflation exists. Too many investors still treat any low-volatility asset as “safe.” It isn’t. An asset that loses 1% (or more) per year in real terms, quietly and without drama, is doing damage that a volatile asset with positive real returns isn’t. Safety isn’t about smoothness. It’s about purchasing power surviving.
The closest thing to a genuine exception is inflation-linked bonds, when they offer positive real yields. But real yields aren’t always available. And if you want to lock them in for a long duration, the instrument itself becomes volatile. There’s no free lunch, even here.
The second job is growth. And this one is almost never discussed properly.
Large losses require enormous gains to recover. Lose 50%, you need 100% to get back to even. This isn’t a motivational poster, it’s arithmetic. The mathematics of compounding punish left-tail outcomes disproportionately. This is what makes diversification not just defensive, but generative.
Days where everything sells off simultaneously are common. But extended periods, however long, where every component of a genuinely diversified portfolio drops 40% or more? Those are effectively zero. That’s not an accident. That’s the whole point.
Here’s the deeper reason this matters: investing is multiplicative, not additive. Returns compound. Losses scale you down, not just back. A catastrophic drawdown in a stock-only portfolio isn’t a setback you recover from linearly, it’s a shock that restructures the entire trajectory of your wealth. This is what non-ergodicity means in practice. The average outcome and your outcome diverge, permanently, after a large enough loss.
Diversification truncates that left tail. And by doing so, it raises your long-run geometric growth rate: not by finding better assets, but by removing the outcomes that would have destroyed compounding altogether.
Diversification isn’t just portfolio insurance. It’s ergodicity restoration. It’s the mechanism that keeps your long-run path from collapsing into one catastrophic draw.
“Once an investor realizes it’s not in their interest to try to optimize for one week but for long periods of time, it becomes easier to endure a period where something is simply lagging or to endure when a diversifier that is intended to offset equity volatility does just that.”
Roger Nusbaum
Diversification works because it doesn’t always work.
That’s not a paradox. That’s the mechanism.
If diversification delivered smooth, consistent, obvious results every single quarter, every investor on the planet would do it. And the moment everyone does it, the edge disappears. The pain and the doubt aren’t bugs in the strategy, they’re the toll you pay to access the return. They’re what keeps the arbitrage alive.
Think about what diversification actually is at its core: a way to manufacture alpha without finding a better stock. The combination of assets, properly constructed, produces a risk-adjusted return that none of the components could achieve alone. That’s not magic. That’s correlation math doing quiet, unglamorous work over long time horizons.
Now think about the opposite. The “boomer candies”, those dividend-heavy strategies engineered to feel good. Regular income, low drama, something to show for your patience every quarter. Retail investors stay invested because the strategy feels safe. It provides comfort.
And that comfort is exactly why it underperforms.
Coziness has a price. When a strategy makes it easy to hold on, you’re paying for that ease in expected return. The market charges you for the smooth ride. It always does.
Which means there’s a trade on the other side of that comfort. Strategies that are genuinely uncomfortable to hold: diversifiers that bleed slowly in good markets, hedges that do nothing for years, positions that invite constant second-guessing. Those strategies pay a premium precisely because they’re hard to own.
The catch is you have to actually own them. Through the questions. Through the underperformance. Through the conversations where you have to explain why part of your portfolio exists at all.
Your strategy will be questioned all. the. time.
That’s not a warning. That’s the signal you’re doing it right.
(I know by posting this image I’ll jinx it…but we are risk underwriters, innit?)
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