Strong economic momentum is a double-edged sword for US equity traders. Solid growth serves as an earnings tailwind for the S&P 500, but let it run too hot and it turns from blessing to curse. Hotter data forces the Federal Reserve to maintain restrictive policy longer, pressuring valuations.

Traders now face a paradox: good news on the economy becomes bad news for stocks as it delays rate cuts. The S&P 500's recent rally has priced in a soft landing, leaving little room for upside surprises on growth. Meanwhile, sticky inflation risks remain elevated.

This dynamic creates a narrow path for further gains, where any acceleration in activity could trigger a reassessment of the rate outlook. Investors must weigh the benefits of resilient profits against the threat of higher-for-longer rates. The market's sensitivity to economic surprises has intensified, making each data release a potential catalyst for volatility.