Diversification 101: don't put all your eggs in one basket

Drop a basket of eggs and you lose the lot. Spread those eggs across a few baskets, and dropping one still leaves you with breakfast.

That's the whole idea behind diversification. In investing terms: don't put all your money into one stock, one sector, or one country. Spread it around, so no single bit of bad news can wipe out your whole portfolio.

It sounds simple, and it is. But it's also the most useful habit you can build as a new investor, more useful than picking the one 'right' stock, and a lot easier to get right.

When you're new to investing, it can at times be tempting to go all in on one company you believe in, or one theme everyone's talking about. And sometimes that works out. But more often it doesn't, and when that happens, there's nothing in your portfolio to soften the blow.

Diversification doesn't stop things from going wrong. It just means that when one part of your portfolio has a bad week, another might not, so your overall returns are smoother and less dependent on a single bet paying off.

Diversifying isn't just about owning more things. It's about owning things that don't all move for the same reasons. There are a few different ways to do it:

• Asset class: stocks, funds, bonds and cash (or cash-like funds, such as money market funds) react differently to the same news. A portfolio that's all-in on stocks will swing harder in both directions than a portfolio that mixes in bonds or funds.
• Geography: it's easy to assume a "global" fund gives you truly global exposure, but many popular global trackers are 60-70% weighted to the US*. Different economies don't move in lockstep, so if you're not paying attention, your "global" portfolio might just be a US portfolio with extra steps. Spreading deliberately across regions means you're not tied to the fortunes of one economy.
• Sector: industries have their own cycles. Consumer essentials, energy, healthcare and tech don't all rise and fall together, so spreading across sectors smooths out the bumps over time.
• Supply chain: two companies in completely different sectors can still rise and fall together if one depends heavily on the other: a chipmaker and the phone brand that uses its chips, for example. Knowing those links helps you diversify vertically, not just sideways.
• Company-level: even within one sector or one fund, your money can end up concentrated in just a handful of names.

Yes and no. An ETF (exchange-traded fund) bundles many companies into a single investment, so buying one already spreads your money across a basket of holdings instead of a single stock. For most people starting out, a broad ETF is a genuinely good first step.

But 'broad' doesn't always mean 'balanced'. Some ETFs track a specific theme or sector, so they move with that one story. And even broad, well-known indices can be quietly dominated by a small number of giant companies, so you're more exposed to a handful of names than the fund's name suggests. An ETF is a great tool for diversification, just not the whole toolkit.

Do you own more than one ETF? Worth checking whether they actually hold different things. It's easy to end up with three funds that all lean heavily on the same handful of companies underneath. On Lightyear, check out Look-through Holdings in your Insights section to see the underlying assets across all your ETFs in one place. That way you can spot that kind of overlap instead of guessing at it.

• Putting most (or all) of your money into one stock or one hyped up theme.
• Assuming a fund is automatically diversified just because it holds lots of companies.
• Buying several funds without checking whether they overlap, and ending up with the same handful of companies three times over.
• Chasing last year's best performers, rather than sticking to a spread that matches your own goals.
• Confusing "more investments" with "more diversified." Ten similar bets aren't more diversified than two very different ones.

You don't need a perfect strategy on day one. A sensible starting point can look like this:

• Start broad. A low-cost, widely diversified ETF is a solid base for most beginners.
• Don't stick with just one asset class. Once you've stepped your toes in with one, research and add more to your portfolio.
• Spread geographically as your portfolio grows, rather than staying tied to one place.
• Check for overlap once you own more than one fund, so you know what you actually hold underneath (tools like our Look-through Holdings help with this).
• Revisit occasionally, not obsessively. Diversification is a habit, not a one-off task.

Diversification won't guarantee a profit, and it won't remove risk entirely. Nothing in investing does. But it's the simplest, most reliable way to avoid taking on more risk than you meant to, and it's a habit worth building from your very first investment.

Footnote: the MSCI World Index sits at over 70% US, and even the more balanced FTSE All-World is above 60%.