The emergence of China-based AI app DeepSeek sent shares plummeting on Monday for many U.S. tech giants, including chipmaker Nvidia and AI-backer Microsoft. Nvidia, which helped catapult market wide gains in recent years,

DeepSeek topped the Apple App Store chart and sparked fears the Chinese company was quickly catching up with OpenAI's ChatGPT while costing far less.

In a matter of days, DeepSeek proved to be so popular as to climb to the top of Apple's App Store, surpassing OpenAI's ChatGPT as the most downloaded app. But for owners of Nvidia stock, and stock traders in general, DeepSeek is on track of becoming a black swan — an unexpected event with extreme consequences.