For years, the US equity market has been dominated by a handful of mega-cap tech names, the so-called “Magnificent Seven”: Apple, Microsoft, Amazon, Alphabet, Tesla, Nvidia and Meta. Their stellar performance has rocketed US and global indices higher, but it has also created risk of extreme concentration.
Today, the top 10 US stocks account for roughly 35% of the market, up from 18% a decade ago. This means that portfolios tied to broad benchmarks are far less diversified than they appear. If any of these giants stumble, the fallout could be swift and severe.
History offers a cautionary tale. During the dot-com bubble, the largest 10 stocks surged to 24% of market capitalisation. When lofty expectations collapsed, trillions in value evaporated. While concentration doesn’t guarantee a downturn, it erodes diversification and amplifies vulnerability.
In my view, investors should be asking a simple question: how much of your wealth depends on a single theme? Periods of narrow leadership often precede weaker returns. While riding the US tech wave paid off over the last decade, piling into one sector or region is now a risky gamble.
In my view, investors should be asking a simple question: how much of your wealth depends on a single theme?
Our 2026 outlook spotlights overlooked opportunities in US small caps. Lagging behind for years, these stocks are now attractively priced and offer a smart route to sidestep the mega-cap trap. Similarly, US healthcare shines as a rare bright spot: robust fundamentals and real pricing power make it an attractive sector amid frothy valuations elsewhere.
But I must stress, despite solid performance of the S&P 500 in recent years, international diversification is vital for investors looking for real returns long-term.
For example, this year through October, the Morningstar Global Markets ex-US Index outperformed the US market by 10.6% in dollar terms. And there are so many regions across the pond that remain undervalued.
Take emerging markets for example, where Brazil, China and Mexico continue to offer upside potential. Then in developed markets we see reasonable valuations in the UK and continental Europe trade.
Of course, not all countries are equal – our analysis highlights Denmark, Portugal and the Netherlands as most undervalued, followed by Germany and France. With Eurozone economic improvement and low valuations, investors may want to act quickly on these opportunities.
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This is where I see some of the most compelling picks for 2026. European markets, in particular, offer a mix of stability and growth at attractive prices. Healthcare, technology and consumer defensive sectors stand out as areas where fundamentals remain strong and valuations reasonable.
Our top calls for each sector include five-star Wolters Kluwer in tech, spirit giant Diageo and biotech leader Roche.
Investors should reduce dependence on a single theme and embrace opportunities across small caps, emerging markets and undervalued European sectors. Diversification isn’t just prudent, it’s essential.
As we head into 2026, investors need to be clear on their diversification. Look beyond the obvious, embrace global opportunities and position for a market where stock leadership will eventually broaden.
Michael Field is chief equity strategist at Morningstar
