Chip stocks fell 15.4% in October as Nasdaq posted its worst month since March 2025

US stocks closed October with the Philadelphia Semiconductor Index (SOX) down 15.4% for the month and the Nasdaq Composite down 5.3%, its worst month since March 2025; the S&P 500 technology sector fell 6.8% for October, also its worst month since March 2025. By contrast, the S&P 500 slipped only 0.9% for the month and the Dow Jones Industrial Average rose 1.7%, showing the sell-off was concentrated in technology and chip stocks rather than the whole market.

Final session led the rout

On the final session, 30 October, the SOX plunged 7.2% to close at 10,688.80, its worst day since 23 June; the Nasdaq fell 2.86% to 25,437.00; and the S&P 500 fell 1.82% to 7,580.07. Among individual names that day, Intel plunged 28.6%, its worst day since 1974, while Nvidia fell 4.2%, AMD 10.9%, Broadcom 5.5% and Micron 5.3%.

Trigger: earnings revived the AI-spending question

According to Reuters, as cited by multiple outlets, the 30 October sell-off was triggered by earnings from Intel, Alphabet and Amazon, which revived investor questions about when heavy AI infrastructure spending will translate into matching returns. The Nasdaq closed October 7.8% below its 6 October record close. This article is the full-October wrap, distinct from the 30 October single-day report published on this site on 31 October; it makes no market forecast.

Sources: Reuters via multiple outlets; TheStreet/Briefing.com monthly data.