US growth stocks underperformed in early 2026 amid AI disruption fears and an unresolved conflict in the Middle East. But these stresses could create favorable conditions for selective, diversified investors to unlock long-term growth potential in a rotating market.

High concentration makes it hard for diversified active portfolios to outperform. While the mega-caps include great businesses, active strategies may avoid or underweight popular stocks over concerns about valuations, business models and interrelated risks, or because of regulations on weighting individual holdings.

Market concentration rewarded passive investors who held market weights in the surging mega-caps. Since late 2014, passive index returns ranked in the 10th percentile of all portfolios in eVestment’s US Large Cap Growth Equity universe. In other words, only 10% of active managers outperformed.