It’s easy to treat the number of holdings as the measure of diversification. Twelve funds sound safer than three, and a long statement looks like careful work.
But a count says very little about risk. What matters is what the investments are and whether they behave differently from one another when markets get difficult.
Overlap
Diversification is meant to stop any one disappointment from doing too much damage, and a new holding only helps if it brings something the existing ones don’t. A US equity fund, a global equity fund and a technology fund sound like three different investments, but all three could have sizable positions in the same American technology companies.
That happens more often than people expect. Funds from different providers, with different names and labels, can hold many of the same shares, particularly if they cover similar parts of the market. Some overlap is normal, and not a problem in itself; what matters is how much exposure it adds up to. So it’s worth checking what’s inside; a fund’s factsheet usually shows its largest holdings and sector exposure.
Correlation
Correlation describes how closely two investments move together and is an important part of diversification. If they rise and fall in step, one does little to cushion the other, so owning several funds that track the same market adds less than it seems. When investments respond differently to market conditions, combining them can smooth the overall ride, though how much depends on what they are and how much of each you hold.
There are limits. In a sharp, broad fall, many things drop together, so diversification can soften losses but doesn’t remove them. Relationships also change over time, and two holdings that looked quite different over one period can look much alike in the next.
Each holding needs a job
A fair test for any holding is whether you can say why it’s there and how it differs from the others. If the honest answer is that it looked interesting at the time, it may not be earning its place.
It also helps to look beyond individual funds: a portfolio can hold shares across dozens of countries and still be heavily exposed to stock market risk. So the balance between shares, bonds, cash and other investments may matter more than adding another fund from a different provider.
Unnecessary holdings can make a portfolio harder to monitor and may add costs, particularly when they sit across several providers or platforms. A smaller number of well-chosen, broadly diversified funds may do more than a long list of overlapping ones. Quality here means how the portfolio is put together, not how impressive each holding looks on its own, since five excellent companies can be less diversified than one global fund.
Accounts built up over time
Anyone who’s lived and worked in more than one country tends to collect accounts along the way. You might have a pension from one place, an account opened with a provider in another, and a workplace scheme from a former employer. Each made sense when it was set up, but they are rarely planned together, and the owner is often the last person to have seen them all side by side.
The result can see several providers holding the same large international companies, with the whole leaning towards one country, often the one the investor lives in or comes from. That’s concentration, even when it’s spread across many accounts, which is why diversification is best judged across everything the investor owns, not account by account.
That doesn’t mean combining everything into one. Some older pensions and investment arrangements carry benefits, tax treatment, or guarantees worth keeping, and moving them can bring its own charges. The first step is to understand the whole position, not move money. Moving between countries can also change which accounts are still the right home for it, so it’s a sensible time to review.
While often dismissed, currency exposure needs the same attention. Holding more than one currency can make sense, but what matters most is the currency you'll eventually spend the money in. The currency on a fund statement isn’t necessarily where the real exposure lies, since a fund priced in pounds may hold mostly overseas investments. The aim isn’t to avoid foreign currencies, but to understand how they affect the money needed and to choose that risk, not inherit it.
Starting from the purpose
A better starting point than the number of holdings is what the portfolio is actually for. How much risk can the investor genuinely sustain, in which currency will the money be spent, and over what period?
With those answered, the questions do get simpler. Does each holding contribute, are they exposed to different things, and are any of them doing the same job twice?
You will find that exercise tends to shorten the list. However, now and then it lengthens it because it reveals a gap the existing holdings missed. Either way, the number ends up being a by-product of the purpose.