AI investment worries contribute to US technology sell-off

The semiconductor index fell 5.4 per cent and the technology sector 2.1 per cent on 18 August 2026, with rising yields, oil prices and scrutiny of AI capital expenditure among the causes. The S&P 500 fell 0.6 per cent and the Nasdaq 1.2 per cent, according to news reports.

Market sensitivity to evidence of utilisation, financing and cash flow is increasing. A single day's price move has many causes; the longer-term capital-expenditure concern is a matter for analysis.