AI Mega-Caps Drive S&P 500 Growth Amid Market Divergence
AI-focused mega-cap stocks are driving the S&P 500 rally while nearly 40% of the index's constituents experience declines.
The S&P 500 rally in 2026 is defined by a sharp divergence between a small group of AI-focused mega-cap stocks and the broader market. While the index continues to rise, nearly 40% of its constituents have declined, creating an unprecedented gap between growth and value stocks.
Leo Nelissen, founder of Main Street Alpha, reports that AI infrastructure spending now drives more than half of the index's earnings per share growth. This concentration of gains suggests that the overall market strength is heavily reliant on a few dominant players rather than broad economic growth.
Market broadening is expected to return once AI momentum normalizes and interest rates stabilize. Analysts anticipate that the broader market will recover as downstream earnings begin to benefit from the current wave of artificial intelligence capital expenditures.
