U.S. tech stocks, including Nvidia, Oracle and Google, plummeted Monday after Chinese startup DeepSeek said it created an AI system that can compete against chatbots such as OpenAI's ChatGPT at much lower costs.

A month ago, almost no one in the U.S. had heard of the Chinese artificial intelligence start-up DeepSeek. Today, its reported breakthroughs prompted the erasure of hundreds of billions of dollars in market value from some of the world’s biggest companies.

A frenzy over an artificial intelligence chatbot made by Chinese tech startup DeepSeek was upending stock markets Monday and fueling debates over the economic and geopolitical competition between the U.