Updated

Surging Treasury yields, which have climbed to multi-decade highs since early September, have begun eroding stock market gains across most sectors. Technology was the only one of the S&P 500's 11 sectors to post gains since September 1, while previously strong performers in other areas have been quietly hit. Analysts note that with bond yields rising, stocks are increasingly serving as their own hedge against volatility, since the traditional refuge of bonds has become less effective. The divergence highlights growing market concentration risk, as investors crowd into a narrow group of large tech names even as higher yields pressure the broader market.