Advances in artificial intelligence by Chinese upstarts rattled U.S. markets on Monday, with the threat of greater competition prompting a slide in shares of the biggest technology companies.

The Chinese A.I. company DeepSeek has said it can match the abilities of cutting-edge chatbots while using a fraction of the specialized computer chips that leading A.I. companies rely on. That’s prompted investors to rethink the heady valuations of companies like Nvidia, whose equipment powers the most advanced A.I. systems, as well as the enormous investments that companies like Alphabet, Meta and OpenAI are making to build their businesses.

On Monday, the S&P 500 index fell 1.5 percent, and the tech-heavy Nasdaq dropped 3.1 percent. Nvidia was hit hard, plunging 16.9 percent and losing roughly $600 billion in market value. Falling tech stocks also dented market indexes in Europe and Japan.

Read the full article…