Chinese startup DeepSeek's cheaper AI is sharpening investor scrutiny of the billions U.S. tech giants are pouring to develop the technology and analysts say it will dominate this week's much-awaited results from industry bellwethers.

Nvidia shares closed down almost 17%, posting its biggest drop since March 2020 and erasing nearly $600 billion from the company's market cap. Broadcom fell 17.4%, and other chip stocks like Micron declined 11.

The tech-heavy Nasdaq index lost nearly 2.7 percent in early trading, with chipmaker Nvidia down nearly 12 percent.