Futures were sharply falling on Tuesday as investors continued to ditch technology stocks, with the Nasdaq 100 tumbling more than 2.5%.
European indexes and Asian markets slumped, with South Korea's Kospi diving 10%, weighed down by chip makers.
The artificial-intelligence rally has gone in reverse in recent days, prompted by jitters over AI companies' heavy spending and looming Federal Reserve interest-rate hikes.
Crude futures were also falling after the U.S. on Monday waived longstanding sanctions on Iranian oil sales for two months.
"The market is becoming more selective: fewer energy-shock fears, but more concern about rates, tech positioning and policy uncertainty," Tickmill Group said.
