New Delhi, Aug. 22 -- Billions of dollars are pouring into the AI buildout, racing ahead of Wall Street forecasts and leaving analysts playing catchup.

A Barron's analysis of more than a decade of analyst forecasts shows capital expenditure estimates for hyperscalers including Alphabet, Amazon, Microsoft, Meta, and Oracle are being revised upward at historic rates.

Those miscalculations can cost investors. Last month, shares of Alphabet fell 7% the day after it announced plans to spend as much as $205 billion this year, up from its prior guidance of no more than $190 billion.

Other hyperscalers fell along with it, as investors grappled with how much Big Tech will have to spend to keep pace in the AI race. Hyperscalers collectively spen...