AI Rotation, Earnings Quality and Market Breadth
AI infrastructure demand and mega-cap earnings continue to support SPY, with Nvidia and Broadcom helping drive roughly 31% S&P 500 earnings growth. Leadership remains narrow: equal-weight and small-cap breadth are weak, semiconductors are volatile, and uncertain hyperscaler capex monetization leaves the rally vulnerable to an earnings or valuation reset.
Sources (28)
Updated Sep 17, 2026