Wall Street presses Big Tech to justify its AI spending spree

A session that erased nearly $800 billion from the Magnificent Seven has investors demanding proof the AI buildout can pay for itself.

The Philadelphia Semiconductor Index posted its worst week since April 2025, sliding roughly 10 percent, while the S&P 500 fell 1.6 percent and the Nasdaq 100 dropped 4.1 percent over the same stretch. The Magnificent Seven suffered their steepest one-day decline since April's tariff-driven selloff, wiping out about $797 billion in value in a single session. Alphabet, Microsoft, Amazon and Meta together are projected to spend roughly $725 billion on AI infrastructure this year, climbing toward $900 billion in 2027, and investors are increasingly unconvinced the returns justify it. Earnings from Tesla and Alphabet on Wednesday, followed by Microsoft, Meta, Apple and Amazon the next week, will be the next test of that patience.