The US stock market has never been this fragmented: The 52-week correlation between the equal-weighted S&P 500 and the S&P 500 index is down to 0.67, its lowest level on record. This measures how closely the performance of the equal-weighted S&P 500 tracks the cap-weighted inde

The US stock market has never been this fragmented: The 52-week correlation between the equal-weighted S&P 500 and the S&P 500 index is down to 0.67, its lowest level on record. This measures how closely the performance of the equal-weighted S&P 500 tracks the cap-weighted index, with a lower reading indicating a growing gap between the broader market and mega-cap stocks. The correlation has declined -0.25 points since August 2025. By comparison, before the 2020 pandemic, this figure remained between 0.95 and 0.99 for nearly 15 years. To put this into perspective, during the 2000 Dot-Com Bubble, this metric never declined below 0.85. The S&P 500 is more concentrated than ever.