US small caps surge ahead: what's driving the market shift now

• Energy sector drives gains: Small caps hold 6.5% energy weighting versus 3.5% in S&P 500, with small-cap energy stocks up 41% compared to 29% for large-cap energy amid rising oil prices
• Multi-year earnings cycle begins: Capital spending incentives including 100% depreciation on CapEx, AI-driven productivity gains, and reshoring trends are boosting margin expansion for smaller firms
• Valuation discount attracts rotation: Small caps trade at lower multiples than large caps despite recent gains, drawing investor capital away from concentrated megacap tech positions into undervalued cyclicals

Summary

Market Shift: US small-cap stocks are significantly outperforming large caps in 2026, with an 8.5 percentage point advantage year-to-date. The S&P SmallCap 600 Index has gained 6.8% while the S&P 500 declined 0.49%, reversing approximately six years of small-cap underperformance.

Key Drivers:

Sector Composition: Energy's outperformance is amplifying small-cap gains. Energy represents 6.5% of the S&P 600 versus 3.5% of the S&P 500. Small-cap energy stocks have surged 41% compared to 29% for large-cap energy, demonstrating higher operational leverage to commodity prices.

Technology Weakness: Technology comprises one-third of the S&P 500 but only 12% of the S&P 600. Concerns around AI valuations have weighed more heavily on large-cap indices, creating a structural advantage for small caps.

Earnings Momentum: Small caps are benefiting from an early-stage multi-year earnings cycle driven by capital spending, AI-driven productivity gains, and reshoring trends. Policy support includes 100% depreciation on capital expenditures and research from the "One Big, Beautiful Bill," fueling a strong CapEx cycle.

Valuation Appeal: Small caps trade at discounted multiples versus large caps, attracting rotation away from concentrated megacap positions into undervalued cyclical segments.

Expert Perspective: Francis Gannon of Royce Investment Partners emphasized this represents "the beginning of what will be a prolonged period of outperformance" supported by strong fundamentals, margin improvements, and market broadening.

Investment Quality: The market is increasingly favoring higher-quality small-cap firms with strong earnings and cash flow, strengthening the sustainability of the rally.