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

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 .

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.