S&P 500 hits record close as only 20 stocks make highs, echoing March 2000 dotcom peak

The S&P 500 ended the last trading day of May at a record close, but only 20 constituents posted their own all-time highs, most tied to AI-related themes. Bank of America's Michael Hartnett compared the narrow leadership to March 2000, while May's surge was led by chipmakers such as AMD (+50%) and Micron (+85%).