New Delhi, Nov. 3 -- Wall Street has reached an inflection point on the AI trade, the investment theme that has single-handedly powered all four years of this bull market. Questions about Big Tech's massive AI spending and its place in the economy are dragging stocks down into the year's final stretch, when history shows they should be riding high.

Since the Nasdaq Composite hit a record peak just shy of a month ago, on Oct. 6, the index has slumped more than 7.5%-and is dangerously close to drifting into correction territory, defined as a 10% pullback from a previous high.

The PHLX Semiconductor index, Wall Street's benchmark for the chip stocks fueling the AI buildout, has already suffered a correction and then some. Since its record ...