Robust gains by Chinese tech stocks have added billions of dollars in their market capitalization, driven by the sudden rise to fame by homegrown AI app DeepSeek.

But the story of DeepSeek also reveals just how much Chinese technological development continues to depend on the United States. DeepSeek used chips from the U.S. giant Nvidia to create its model, and, as it turns out, may have also tapped American data to train it. Washington can capitalize on that advantage to choke off Chinese tech firms.

The meteoric rise of DeepSeek—the Chinese AI startup now challenging global giants—has stunned observers and put the spotlight on China’s AI sector. Since ChatGPT’s debut in 2022, the country’s tech ecosystem has been in relentless pursuit of homegrown alternatives, giving rise to a wave of startups and billion-dollar bets.

A security expert warns “Deepseek,” the no. 1 downloaded app on Apple and Google, could pose potential privacy concerns for American users.