Global equities have climbed 11.5% year to date in 2026, but the rally is driven almost entirely by artificial intelligence and infrastructure, with just two industry groups accounting for 86% of those gains, according to MSCI’s midyear update released in late July.
The concentration of gains in semiconductors and infrastructure reflects the outsized investment in AI buildout, as companies race to develop and deploy artificial intelligence systems. BlackRock noted in December 2025 that AI investment is expected to surge $5 billion to $8 trillion through 2030, fueling demand for chips, data centers, and energy infrastructure.
This level of market concentration is historically extreme. According to Morningstar research from December 2025, the top 10 U.S. stocks reached 37.7% of total market value by October 2025, surpassing the concentration levels of the 1930s Great Depression era. The CFA Institute reported in April 2025 that the U.S. stock market had reached its highest concentration in more than 50 years, with the top 10 stocks comprising 36% of the market’s weight.
The narrow leadership mirrors patterns from previous technology booms. In 2024 and 2025, tech stocks dominated returns for the third consecutive year, with communication services and technology combined driving the bulk of S&P 500 gains, according to Fidelity’s 2025 stock market report.
Analysts warn that while AI-driven earnings growth is real, the market’s dependence on a handful of names leaves less room for error. MSCI’s research noted that while AI proved the stronger market force through 2026’s first half—absorbing geopolitical tensions without derailing the rally—the open question is how durable that dominance is and whether AI-led earnings can broaden beyond semiconductors and infrastructure into other sectors.
Sources
- MSCI — Global equities up 11.5%, two sectors drive 86% of gains, July 2026 midyear report
- BlackRock — AI investment surge and capex outlook through 2030, December 2025
- Morningstar — Top 10 stocks reached 37.7% of market value, concentration surpasses 1930s peak, December 2025
- CFA Institute — U.S. stock market concentration at 50-year high, April 2025
- Fidelity — Tech and communication services drove 2025 returns for third straight year, 2025 report
