Stocks Face ‘Critical Tipping Point’ as Key Thresholds Tested

A suddenly turbulent US equity market has traders studying technical charts for clues on where the latest bout of selling might stall out.

Doubts around whether the billions of dollars being invested in artificial intelligence will pay off, combined with still-lofty stock valuations sent the S&P 500 Index down to 6,720.32 on Thursday, the lowest level in two weeks. From here, the 50-day moving average of 6,665 looms as a major line of defense, chart watchers say.