US week in review — Saturday, June 27, 2026

S&P 500 ends the week down 1.9% as an AI-chip rout sinks the Nasdaq 4.6%; biotech and defensives lead a rotation

US stocks split this week. The Nasdaq lost 4.6% and the S&P 500 fell 1.9% as a report that OpenAI may delay its IPO triggered a semiconductor selloff, but the Dow rose 0.6% and the Russell 2000 gained 1.0% as money rotated into biotech, health care, utilities and staples. A hot core PCE print of 3.4% closed the week.