Imagine it is 1989…
You open a financial newspaper. At the time, everyone is talking about Japan. Japanese markets are breaking record after record, and many experts are convinced the country will dominate the global economy for decades to come.
For many investors, looking elsewhere had barely seemed to make sense any more.
And yet, a few decades later, Japan now accounts for only around 6% of global stock market capitalisation...
« Diversification is an essential safety measure, because we must be humble enough to admit that we may be wrong. »
Market history reminds us of a simple reality: no country, sector or company stays on top for ever.
Why is it important to diversify your portfolio?
👉 Diversifying your portfolio means spreading your investments across several assets in order to limit risk.
The aim is not to maximise performance, but to avoid letting a single country, sector or company determine your portfolio's results on its own. No one knows who tomorrow's winners will be. Diversification means you do not have to guess.
💡 Did you know?
Holding only Apple, Microsoft, Nvidia, Amazon and Meta may give the impression of being well diversified.
Yet your portfolio still remains heavily dependent on:
- ✅ the United States;
- ✅ the technology sector;
- ✅ the same economic drivers.
Diversifying does not mean buying more shares. It means investing in assets that do not all react in the same way.
🎯 What you’ll learn in this guide
In this guide, we answer one essential question: how do you build a genuinely diversified portfolio? The five strategies below will help you create a more robust portfolio, better able to withstand different market conditions.
🔍 Which broker should you choose to diversify your portfolio effectively?
To put the strategies presented in this article into practice, choosing the right broker is almost as important as choosing the right investments.
Ideally, you should choose a platform that offers:
- ✅ broad access to international markets;
- ✅ several thousand ETFs;
- ✅ bonds and other asset classes;
- ✅ direct ownership of shares and ETFs;
- ✅ competitive dealing fees.
👉 Not sure which broker to choose? We've compared the leading UK share dealing accounts based on fees, available markets, ETFs, investment products and overall features to help you find the platform that best suits your investing needs.
You can then put the various diversification strategies outlined below into practice.
Still looking for the right broker? Discover our ranking of the best UK share dealing accounts.
#1 - Diversify your investments geographically
The first dimension of diversification is often the one investors underestimate most: geography.
One of the most common mistakes is to invest primarily in your home country or region. A British investor will often favour FTSE 100 stocks. An American investor will naturally be drawn to Wall Street. This behavioural bias is so widespread that it even has a name: home bias.
Economic history shows that no power dominates the financial markets for ever. Japan is a particularly striking example: at the end of the 1980s, it accounted for nearly 45% of global market capitalisation. Today, Japan represents only around 6% of it.
Why invest across several regions of the world?
| Region | Why invest there? |
| United States | Innovation, artificial intelligence and global large-cap companies |
| Europe | Industry, healthcare, luxury goods and international businesses |
| Japan | Robotics, automotive and major industrial companies |
| 🌍 Asia | Economic growth and the expansion of the middle class |
| 🌍 Emerging markets | Long-term growth potential |
No region performs well all the time. Economic cycles change, as do the sectors that drive markets. Spreading your portfolio across several geographic areas helps limit the risk of relying on a single growth engine.
A global portfolio is generally better placed to cope with difficulties in any one specific region.
🔍 A detail that is often overlooked
When you invest in foreign markets, remember to check the foreign exchange fees charged by your broker. Over the long term, these costs can erode your portfolio's overall performance and reduce your investment returns.
#2 - Spread your investments across several sectors
Holding twenty technology stocks does not amount to genuine diversification. The year 2022 demonstrated this perfectly. When interest rates rose sharply, many technology shares fell at the same time.
By contrast, some more defensive sectors proved more resilient.
Why diversify across different sectors?
| Sector | Typically favoured when… |
| 📊 Technology | the economy is growing |
| 📈 Finance | interest rates are high |
| 🛡️ Healthcare | the economy is slowing |
| ⚡ Energy | commodity prices are rising |
| Consumer | consumer spending is recovering |
| 🌍 Industry | business investment is accelerating |
A portfolio made up solely of technology stocks can therefore deliver exceptional performance… but it can also suffer significant corrections when the economic cycle turns.
For example:
- ✅ Banks often benefit from higher rates
- ✅ Technology shares tend to benefit more from a growth environment
- ✅ Healthcare remains relatively resilient even during periods of economic slowdown
- ✅ Energy depends heavily on movements in commodity prices.
Spreading your investments across several sectors helps prevent a single economic trend from determining your portfolio's overall results.
#3 - Use ETFs to gain immediate diversification
ETFs have profoundly changed the way people invest. Just twenty years ago, building a diversified global portfolio meant buying many individual shares, sometimes across several stock exchanges.
Today, a simple MSCI World ETF allows you to invest in more than 1,300 companies across the main developed economies. It is worth noting, however, that the United States makes up between 60% and 70% of most MSCI World ETFs. This concentration simply reflects the current weight of American companies in developed markets. Holding only this one line in your portfolio does not provide truly diversified exposure. An MSCI World ETF is an excellent diversification foundation, but it does not cover the entire global market. Emerging markets, small caps and certain asset classes remain underrepresented, or even absent. Depending on your objectives, it may therefore be worth complementing this exposure with one or more additional ETFs.
🎁 Practical tip: choose the right ETF platform
To implement this type of strategy, it is important to choose a broker offering a wide range of international ETFs. Not all investment platforms provide access to the same ETF selection, so comparing their offering can help you build a more diversified portfolio.
💡 Did you know?
Many investors believe that an MSCI World ETF offers balanced exposure to the whole world. In reality, its composition is currently far from evenly distributed...
| Main exposures | Approximate weighting |
| United States | ≈ 72% |
| Japan | ≈ 5% |
| United Kingdom | ≈ 3% |
| Canada | ≈ 3% |
| France | ≈ 2.5% |
In other words: a portfolio made up solely of an MSCI World ETF still remains heavily dependent on the US economy today.
With just a few ETFs, it is possible to gain exposure to:
- ✅ the global economy
- ✅ emerging markets
- ✅ specific themes (commodities, for example)
- ✅ different sectors of activity.
For many retail investors, ETFs are probably the most effective diversification tool ever created. They make it possible to significantly reduce company-specific risk while maintaining exposure to market growth.
#4 - Do not put all your eggs in the equities basket
Even a portfolio made up of hundreds of shares remains exposed to the same asset class. Yet financial markets move in cycles. Some periods favour equities. Others are more supportive of bonds, property or cash-like assets...
Depending on your risk profile, it may be sensible to include:
- ✅ government or corporate bonds
- ✅ money market funds
- ✅ property (SCPI or listed property companies)
- ✅ commodities
- ✅ crypto-assets
- ✅ and keep a cash allocation.
The goal is not necessarily to seek higher performance. It is mainly about reducing the portfolio's overall volatility and retaining a degree of flexibility when opportunities arise.
An investor with cash available during a stock market crash is generally in a better position than one who is already fully invested.
#5 - Avoid letting a single holding dominate your portfolio
This is probably the hardest mistake to avoid. When a share performs exceptionally well, its weight in the portfolio increases automatically.
Nvidia's spectacular rise illustrates this perfectly. Many investors who bought the share a few years ago saw its weighting gradually rise until it sometimes represented 30%, 40% or even more of their portfolio. Without realising it, they became heavily dependent on the performance of a single company.
The problem is simple: the larger a position becomes, the greater the specific risk... Kodak and Nokia are both historical examples of this danger: shares that once flourished but whose former highs were never seen again.
Even the most admired companies can face:
- ✅ slower growth
- ✅ strategic mistakes
- ✅ regulatory changes
- ✅ the arrival of new competitors.
Warren Buffett can afford to accept a high degree of concentration because he has the resources, a very long investment horizon and exceptional analytical ability. For most retail investors, a more balanced approach is generally preferable. That is why periodic rebalancing is necessary.
Many investors therefore choose to limit the size of any one position to a maximum of 5%, 10% or 15% of the portfolio. This discipline prevents a single investment decision from determining the success or failure of an entire wealth-building strategy on its own.
Diversification can sometimes feel as though it is "holding back performance" when certain assets surge. Yet it is precisely this discipline that often helps avoid the most costly mistakes when the market suddenly changes direction.
The idea is not for all assets to rise at the same time. Quite the opposite. Good diversification rests precisely on the fact that some parts of the portfolio can temporarily offset the weakness of others.
Diversifying your portfolio: key takeaways
Diversification does not protect against every loss. Nor is its purpose to maximise performance.
The real question is not: “How can I maximise my gains?”, but rather: “How can I build a portfolio I will be able to hold with confidence, even during periods of crisis?”
Diversification provides an answer to that question. It is one of the most powerful tools available to investors for limiting unnecessary risk.
Diversifying your investments across several geographical areas, sectors, asset classes and a sufficient number of holdings helps you build a more resilient portfolio in the face of economic uncertainty.
Diversification is not about predicting which asset will perform best tomorrow. It is about building a portfolio capable of weathering very different scenarios without relying entirely on just one of them.
Finally, it is important not to overlook the importance of the broker you use. Access to international markets, ETFs, bonds and certain asset classes can vary considerably from one platform to another. Dealing fees also differ from one broker to another.
A well-chosen broker makes it much easier to put a genuine diversification strategy in place.
