The S&P 500 has climbed nearly 10.73% year-to-date through late May 2026, powered almost entirely by artificial intelligence stocks that now dominate the market’s gains. Data from May 2026 shows that AI-related equities account for over 80% of the index’s gains this year, while the broader market outside of AI remains essentially flat since February, highlighting the concentrated nature of the current rally.
The divergence is stark. According to analysis from May 2026, the S&P 500 excluding AI enablers has declined 1.84% since its February launch, even as the headline index reached record highs. This means that without contributions from artificial intelligence stocks, the market would show minimal gains, underscoring how heavily the 2026 rally depends on a narrow set of technology-focused companies betting on AI infrastructure and adoption.
Investors considering stock market exposure in 2026 should understand this concentration risk. While AI companies continue to drive momentum through strong earnings and investor enthusiasm for the sector, much of the rest of the economy remains sluggish. Geopolitical tensions and economic uncertainty have kept many companies cautious about spending and margin outlooks, leaving limited catalysts outside the AI trade to propel the broader market forward.
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Sources
- Yahoo Finance — AI stocks driving nearly all S&P 500 gains, with ex-AI index down since February as of May 2026
- Macrotrends — S&P 500 YTD performance data showing 10.73% gain as of May 29, 2026
- MSN — AI stocks accounting for over 80% of S&P 500 gains in 2026
