The Russell 2000 gained 43.7% from its April 8, 2025 low through March 31, 2026, outpacing the S&P 500 by 11.1% over that stretch, according to ProShares. For an asset class that spent the better part of a decade in the shadow of large-cap growth, that is a material reversal — and it has practitioners revisiting a structural debate that never fully closed.

The reversal has been broad-based. Fidelity Institutional confirmed small-caps outperformed large-caps for both the trailing 12 months ended March 2026 and in Q1 2026 specifically. In that first quarter, the Russell 2000 added 0.9% while the Russell Microcap index advanced 1.5%, per Royce Investment Partners. On a one-year basis ended March 31, 2026, the Russell Microcap surged 45.8%, per Franklin Templeton, while Royce's USA Small Cap Index logged 27.8% for the same period.

The Long Underperformance in Context

None of this erases a long structural drag. LSEG/FTSE Russell research documents two distinct multi-year periods when small-caps trailed: 1982 to 1998, and again from 2010 through the recent cycle. The second stretch is the more relevant anchor. The S&P 500 outperformed the Russell 2000 by 69% between March 2021 and early 2025, a span defined by pandemic-era multiple expansion in mega-cap tech and then the sharpest rate-hiking cycle in four decades, per CME Group. Small-cap balance sheets, typically carrying more floating-rate debt than their large-cap counterparts, bore the brunt of that repricing.

What changed from April 2025 onward is less about any single catalyst and more about the clearing of that headwind. Rate expectations stabilized, the dollar softened from its 2022–2024 highs, and domestic-oriented revenues — the core small-cap characteristic — held up in a still-resilient US economy.

The Earnings Quality Problem Hasn't Gone Away

The performance data is real. The earnings composition data is also real, and the two need to be held together.

Aristotle Capital puts the current share of Russell 2000 constituents with positive earnings at 61% — down from roughly 85% in July 1994. That 24-percentage-point deterioration in index-level profitability reflects decades of index methodology that admits pre-earnings biotechs, capital-intensive disruptors, and serial cash-burners at IPO. The Russell 2000 is a float-adjusted, reconstituted-annually benchmark, not a profitability screen. Nearly two in five constituents are losing money.

That composition matters for how the recent rally is read. An index-level 43.7% recovery from a trough contains a wide dispersion of outcomes — profitable compounders, speculative re-ratings, and short-covering across unprofitable names that were beaten down alongside everything else in the April 2025 selloff. Aggregate index performance does not discriminate between them.

What Practitioners Should Watch

The historical analogy that keeps surfacing is the 1994-to-1999 period, when small-cap earnings quality was markedly higher than today and the asset class still lagged large-caps for years. Today's index carries a structurally weaker earnings base going into whatever the next macro phase brings. If rates stay higher for longer — or if growth disappoints — unprofitable small-caps face refinancing risk at yields that are still punishing relative to 2019-era baselines.

The case for small-caps is cleaner within profitability-filtered universes, where the divergence between the earnings-positive cohort and the broader index is significant. Active managers who systematically exclude loss-makers have a different exposure profile than passive index holders, and the gap between those two approaches is wider now than it was in the mid-1990s, given how much the index's earnings mix has degraded.

The near-term momentum is genuine. The structural caveat — that the benchmark vehicle many use to access this rally has a weaker earnings foundation than at any point in its modern history — is equally genuine. Both facts can be true simultaneously, and for practitioners allocating across size factors, the distinction between index exposure and quality-filtered small-cap exposure is not semantic. It carries real return-distribution implications.