Alphabet erases more than $500 billion in its worst day ever as AI Mode weighs on search ads

Alphabet shares fell more than 12% on Thursday, the company's worst one-day performance on record, wiping out over $500 billion in market value, the second-largest single-day loss in market history behind Nvidia's $589 billion drop in 2025. The selloff followed third-quarter results that missed Wall Street expectations on revenue and advertising. Chief business officer Philipp Schindler told investors that Google's own AI Mode search feature was producing fewer ads and contributing to weaker search revenue, though he said ad experiments there had shown promising results. Alphabet also disclosed more than $1 trillion in multiyear commitments for AI infrastructure, energy and leases. The drop pulled the Nasdaq down about 1.5% and hit chip stocks and Caterpillar.