A tech sell-off shook global markets on Tuesday as attention turned away from developments in the US war with Iran and toward the future of AI companies and chipmakers that have driven stock markets to record highs.

The tech-heavy Nasdaq index closed 2.2% lower on Tuesday. The S&P 500 was also down by Tuesday afternoon, dropping 1.43% while the Dow remained steady.

All three major US indices have hit record highs this year, riding off a rush of funding to support AI technology and infrastructure. Nasdaq is up 10% for the year, while the Dow jumped 6% so far this year, breaching past 51,000 points, and the S&P 500 is up 7.3%.

But some economists have warned that the influx of AI spending is a bubble reminiscent of the dot-com bubble that…