October ended as a bruising month for United States technology shares, as investors questioned whether the huge sums being poured into artificial intelligence infrastructure will pay off quickly enough. The Nasdaq Composite fell 2.9% on Friday 30 October, the S&P 500 fell 1.8% in its worst daily performance since June, and the Dow Jones Industrial Average declined 1.1%, according to Associated Press reporting of the session.

The trigger was earnings. Intel shares fell about 29% in their worst day since 1974 after weak fourth-quarter guidance, a soft personal-computer market and heavy spending to expand production. Amazon pared an early fall of about 7% to close about 2% lower after reporting a sharp cash outflow and signalling another increase in capital expenditure next year. A day earlier, Alphabet had fallen more than 12% in its worst daily performance on record after disappointing search-advertising results and a surge in cash burn, wiping more than $480 billion from its market value in a session.

An October wipeout

By Friday's close the technology-heavy Nasdaq was more than 8% below its record closing high set on 6 October, and Reuters estimated that the Nasdaq 100 was on course to lose more than $2 trillion of market value across October. Together, Amazon, Google, Microsoft and Meta spent more than $200 billion in the third quarter alone, and Morgan Stanley has estimated that spending on AI infrastructure could exceed $1 trillion in 2027. Markets also expect the Federal Reserve to raise interest rates by more than half a percentage point by mid-2027, according to LSEG data, which would make debt-funded AI spending harder to justify.

What comes next

The sell-off reprices expectations, not artificial intelligence itself: the question is timing, whether returns arrive fast enough to cover the buildout. Attention now turns to the coming week's United States data and Tuesday's midterm elections. This article reports market movements only and is not financial advice.