US Stock: S&P, Nasdaq end lower on semiconductor selloff as AI spending concerns mount

Broad-based equity weakness materialized across major indices as S&P 500 and Nasdaq declined to multi-day lows, with semiconductor equities bearing the brunt of selling pressure. The move reflects a critical inflection point where investor conviction around artificial intelligence capital expenditure is fracturing, raising questions about the sustainability of current valuations relative to actual earnings accretion.

The semiconductor decline is fundamentally driven by two compounding concerns: first, the mounting recognition that debt-financed AI infrastructure buildouts may not generate proportionate returns, and second, expectations of continued monetary tightening. Market pricing now incorporates elevated probability of a second Federal Reserve rate hike by year-end, which compresses terminal value calculations for high-growth, capital-intensive semiconductor firms like NVDA and AMD. Memory chip producers MU and MRVL face additional cyclical headwinds.

The divergence between AI narrative enthusiasm and fundamental repricing represents a classic risk-off rotation. Tech exposure, particularly in semiconductors, is shifting from being viewed as secular growth to cyclical risk, especially as real rates remain elevated and forward earnings estimates face downward revision pressure. Cloud infrastructure clients like GOOGL face indirect margin compression if capex spending moderates.

Sector implication: Technology sector faces duration compression and multiple contraction risk. Defensive rotations may accelerate if Fed hawkishness confirmation deepens, with semiconductor strength unlikely until clarity emerges on AI ROI and rate expectations stabilize.