Nvidia stock plummeted on Monday as news that a Chinese company had built an artificial-intelligence model that was competitive with Western rivals for a fraction of the cost provoked a panic in the chips sector.

It feels like this day was always going to come — when all the artificial-intelligence names collapse — but one might have imagined it would come from, say, a profit warning from Nvidia. Instead, it comes from what appears to be an Nvidia consumer, Chinese AI service provider DeepSeek.