Record share of S&P 500 stocks now trade against the index: the market is hiding its own volatility
The share of S&P 500 members with negative beta to the index just hit a record over a rolling six-month window, meaning more stocks move opposite the benchmark and under-the-surface volatility is higher than the headline index suggests. It is fresh fuel for AI-bear sentiment, even as megacap tech keeps the index near highs.