US macro dynamics: how AI CapEx, margin resilience and Fed policy shifts impact small and mid caps

Only a few months ago, investors were expecting a ‘Goldilocks’ scenario, but inflation pressures have reversed the monetary policy cycle. Despite the Federal Reserve’s decision to raise interest rates and elevated bond yield volatility, US small and mid-cap (SMID) equities continue to display particularly strong fundamentals. Backed by solid Q2 2026 results, upward revenue and earnings revisions across key sectors, and an unprecedented wave of investment in artificial intelligence, small and mid-caps offer stronger earnings growth prospects than broad indices dominated by mega-caps.

Macro and Fed backdrop: policy friction in a cooling economy

The economic background is no longer characterised by a frictionless ‘Goldilocks’ trajectory, but rather by a selective slowdown alongside central bank recalibration:

Cooling aggregate demand: High-frequency consumption metrics, receding tax-refund tailwinds, and real-income pressure from sticky energy costs confirm that past rate hikes continue to drag on broad economic activity. Labour markets have normalised - with the 4.1% unemployment rate driven primarily by participation dynamics rather than mass layoffs - while unit labour costs remain consistent with long-term inflation targets.

Inflation factors: Rigidity in the core personal consumption expenditures index remains concentrated in supply-side categories, supporting the assumption that core inflation will return to its target by 2027, but geopolitical uncertainties remain a significant risk.

Fed policy: the tightening cycle resumes. The rate rise anticipated by the market materialised at the FOMC meeting on 15–16 September 2026. With inflation still above target and the US economy remaining resilient, the Fed raised rates by 25 basis points to 3.75%–4.00%. Its tone remains firmly restrictive, with 16 of the 18 FOMC members expecting at least one further increase by the end of the year. The prospect of a rapid return to a neutral rate of 3.5% has therefore receded, as restoring lasting price stability remains the priority.

The decision was accompanied by a sharp rise in bond yields and interest rate expectations. The 10-year US Treasury yield exceeded 5%, while the 30-year yield reached its highest level in 20 years. Markets now price in a probability of nearly 70% of a further 25-basis-point rise in October. Against this backdrop, interest rate volatility remains a major risk for equity markets, particularly for segments most sensitive to the cost of capital.

Earnings execution and dynamic revisions: SMID outperformance

Microeconomic data highlights a clear divergence between macroeconomic policy noise and corporate earnings delivery:

Strong Q2 2026 results: the Q2 reporting season confirmed solid operational performance, with 64% of Russell 2000 companies beating earnings-per-share (EPS) estimates.

Source: RBC, 20 August 2026

Upward sector revisions: financial analysts are actively revising top-line revenue and bottom-line profit growth expectations upward for the next two years. These positive revisions are particularly concentrated in key SMID-heavy sectors: Information Technology, Industrials, Health Care, and Financials.

Impressive relative growth outlook: consensus earnings estimates point to an unprecedented growth trajectory for small and mid-caps that comfortably outpaces large-cap benchmarks.

SMID-cap consensus growth: expected EPS growth of +43% in 2027 and +28% in 2028 according to Bloomberg at the end of August 2026.

S&P 500 comparison: broad market EPS growth projected at +13% in 2027 and +15% in 2028, according to Bloomberg at the end of August 2026.

EPS Growth

Source: DPAM/Bloomberg

Structural drivers: AI CapEx spillovers and margin defence

The fundamental engine behind these ambitious growth figures rests on two main pillars:

Revenue benefits from AI investment: massive infrastructure investment by technology giants is creating significant spillover effects. This spending, which could contribute around one percentage point to US GDP growth, is feeding order books across specialised small and mid-cap segments: semiconductors, liquid and thermal cooling systems, specialised data centre engineering, grid modernisation, and nuclear and renewable power generation.

Margin resilience: despite elevated borrowing costs and greater exposure to floating-rate debt, small and mid-cap operating margins remain near historical highs. Growing corporate adoption of AI and automation tools is driving broad-based productivity gains, helping to offset wage growth and higher debt-servicing costs.

Strategic conclusion

While the return to tighter monetary policy and interest rate volatility may continue to fuel short-term market noise, the fundamentals of US small and mid-caps remain particularly strong. Supported by solid Q2 results, widespread upward earnings revisions and particularly strong multi-year earnings growth prospects (+43% in 2027 versus +13% for the S&P 500), small and mid-caps offer investors a combination of structural growth and operational resilience.