U.S. Stock Market Widens Historic Lead as China's AI Sector Implodes

The S&P 500 has surged to its widest performance margin over China's stock market in nearly three decades, as a spectacular collapse in China's artificial intelligence sector reshapes global tech investment flows. As of October 22, 2026, the S&P 500 traded at 2.095 times the Shanghai Composite Index—the highest ratio since records began in 1997, exceeding the previous record set in September 2024. Through late October, the American benchmark has gained 11.4% this year while Shanghai fell 7.0%, with Hong Kong's Hang Seng dropping 9.9%.