What if your stock market return depended on a remarkably small number of companies?
Thousands of listed companies exist worldwide, yet just a handful generate a remarkably large share of market value. The ten largest companies in the world currently account for around a quarter of the global stock market, and their share of corporate earnings is as high as nearly 40%. Together, these companies achieve profits of around 350 billion dollars every quarter.
As impressive as these figures are, they also raise an important question: what does it mean for investors when a relatively small group of companies wields so much influence over stock market returns?
When you look at companies like Microsoft, Nvidia, Amazon and Alphabet, it’s easy to think their success was inevitable, but that’s only in hindsight. Twenty years ago, it was by no means a given that these companies would develop into the market leaders they are today.
This brings us to one of the greatest challenges of investing: how to ensure your portfolio has sufficient exposure to current and future winners, without becoming dependent on a single share, sector or trend.
We asked Siegfried Top, Senior Investment Strategist at KBC Asset Management, to shed some light on this matter.
The stock market is driven unevenly
Many investors assume that stock market returns are driven by thousands of companies collectively, whereas, in reality, a large proportion of value is often generated by a relatively small group of companies.
This has a simple explanation: successful companies don’t grow linearly; they grow exponentially. Higher profits allow for new investments, and these investments create further growth opportunities, which in turn can lead to even higher profits, creating a flywheel effect that can keep going for years.
However, there’s also a flipside: while it’s easy to spot the winners after the fact, it’s much harder to predict which companies will maintain their lead. Technology and regulations change, and new competitors emerge.
The biggest stock market winners are rarely one-hit wonders; they are companies that successfully build on their leading position year after year.
Siegfried Top, Senior Investment Strategist at KBC Asset Management
A good example of this is ASML. This Dutch company is the world’s sole supplier of the most advanced machines for manufacturing the latest-generation chips. This competitive advantage gives the company a unique market position.
Yet even a market leader like ASML is not untouchable. In 2026, a Chinese manufacturer launched its own chip machine. Although their technology has a long way to go to compete with ASML’s, it shows the competition isn’t standing still.
The lesson for investors is clear: a strong competitive advantage is valuable, but it cannot be guaranteed forever. Even market leaders need continual reassessment.
Does this mean you should always be on the lookout for tomorrow’s winners?
Not necessarily.
Every investor dreams of getting in early on the next Nvidia, Microsoft or ASML. The problem is that almost no one can accurately predict which companies will take on that role.
Looking back, you will mainly see the success stories. The hundreds of companies that once seemed just as promising but never lived up to their potential are far less visible.
That’s why successful investing isn’t about making one perfect prediction; it’s about making sure your portfolio includes enough of the future big winners once they make their breakthrough.
Many investors overestimate their ability to spot the next big thing. With a well-diversified portfolio, you avoid becoming dependent on a single prediction.
Siegfried Top, Senior Investment Strategist at KBC Asset Management
What makes a company truly exceptional?
While no one can predict the future, many exceptional companies tend to share the same characteristics.
1. A unique competitive advantage
Strong brands, technological leadership, scale advantages or unique platforms make it particularly difficult for competitors to snatch up market share.
This is well illustrated by Nvidia, which has spent decades building up expertise in specialised chips. That knowledge cannot be replicated overnight.
2. Structural growth markets
Exceptional companies are often active in markets with long-term growth potential, such as artificial intelligence, digitalisation, automation, health care or the energy transition. Companies operating in these growth markets benefit from a strong tailwind that can accelerate their growth.
3. High profitability
Growth alone is not enough.
The most successful companies combine revenue growth with profitability, allowing them to keep investing in innovation, new products, or international expansion without constantly relying on external funding.
For example, investors are questioning the huge investments in AI by the likes of Microsoft and Meta, wondering not just how much they are investing, but above all whether those investments will ultimately yield higher profits.
4. Strong leadership
Even the best product is no guarantee of success. In the end, the choices people make determine whether a company will thrive or falter. Successful management teams invest at the right time, change course when circumstances change and dare to make decisions even when the outcome is still uncertain.
Take Nvidia CEO Jensen Huang, for example. Several strategic choices that seemed risky at the time ultimately proved crucial to the company’s growth. Not because taking risks always pays off, but because strong leaders respond to change when it matters and dare to innovate.
Strong leadership combines vision with discipline and the ability to continually adapt your business to a changing world.
Why some winners keep winning for years
The success of many big stock market winners is not down to a single product or innovation. Their real strength lies in their ability to keep reinventing themselves.
Microsoft, for example, went from being a software producer to a cloud giant. Amazon started as an online bookshop and now operates as a global technology and infrastructure platform. Apple transformed from a computer manufacturer into an ecosystem of hardware, software and services.
Today’s biggest stock market winners have often gone through multiple growth cycles. They don’t just owe their success to what they do, but above all to their ability to adapt as markets change.
What does this mean for investors?
Perhaps the most important lesson is that investing is not so much about predicting a single future champion as it is about building a portfolio that leaves room for future winners.
This requires sufficient diversification as well as continuous monitoring. Structural growth trends are constantly evolving. Companies that appear dominant today may be challenged by new technology, competition or changing regulations tomorrow.
At KBC, we continually reassess companies based on their growth potential, profitability, valuation and competitive position.
Investing involves more than just identifying strong companies today; it also requires continuous assessment of whether those companies can maintain their competitive advantage. That’s why many investors opt for a well-diversified, actively managed strategy.
Siegfried Top, Senior Investment Strategist at KBC Asset Management
This can be achieved through an actively and professionally managed approach, combined with a carefully considered underlying strategy – not by predicting a single winner, but by consistently monitoring opportunities and risks, adjusting the focus as market conditions change, and ensuring that no single success story has an excessive impact on the overall portfolio.
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This document is published by KBC Asset Management NV (KBC AM). The information and figures it contains are a snapshot, which may be changed without notice. The information provided offers no guarantee for the future. The information provided should not be regarded as investment advice or as an investment recommendation. Nothing in this document may be reproduced without the prior, express, written consent of KBC AM. This information is governed by the laws of Belgium and is subject to the exclusive jurisdiction of its courts.
