S&P 500 market breadth weakens below key long-term threshold

More than half of the stocks in the S&P 500 are now trading below their 200-day moving averages, marking the weakest market breadth since early April.
The deterioration indicates that weakness is spreading across a larger portion of the index even if headline index levels remain comparatively resilient.
When a majority of constituents trade below their long-term trend lines, the market becomes increasingly dependent on a narrower group of stronger stocks to support the broader index.