A small group of seven companies, including Alphabet, Amazon, Apple, Meta Platforms, Microsoft, Nvidia and Tesla, have become so dominant that they alone contributed to more than half of the S&P 500’s

Shares of Japanese chip-related firms were feeling the heat on Monday. Today’s slump comes as Chinese AI startup DeepSeek gained traction with its updated AI model, raising fears about potential challenges to US technological dominance.

By Sinéad Carew, Amanda Cooper and Ankur Banerjee LONDON/SINGAPORE (Reuters) - Investors made a quick exit from a host of technology stocks from Tokyo to New York on Monday as the emergence of a low-cost Chinese artificial intelligence model challenged the dominance of current AI leaders such as Nvidia .

Chinese startup DeepSeek has shaken the belief that only a few firms with huge budgets can compete in the artificial intelligence field — potentially challenging an investment case that rewarded the biggest players with rich valuations.

The tech-heavy Nasdaq index lost nearly 4 percent in early trading Monday, with chipmaker Nvidia down nearly 12 percent.

Shares in major US technology firms have plunged after the rapid rise of a low-cost chatbot built by a Chinese artificial intelligence (AI) firm. The DeepSeek app, which was launched last week, has overtaken rivals including OpenAI's ChatGPT to become the most downloaded free app in the US.