Tech stocks are leading declines on Wall Street, with worries about AI spurring debates about its future. The Nasdaq Composite is down around 2.4 per cent over the last two days, the worst two-day fall since April.

The central bank's annual conference in Jackson Hole, Wyoming, kicks off on Friday, with Chair Jerome Powell expected to speak, remarks that will be closely watched for policy signals. Investors have been pricing in a 25-basis-point rate cut in September, according to data compiled by LSEG.

A steep slide in shares of semiconductor companies was dragging on the Nasdaq Composite on Tuesday afternoon, putting the tech-heavy index on track for a rare underperformance versus the Dow Jones Industrial Average.