SHARE THIS VIDEO —

Chinese A.I. app shakes up Silicon Valley, causing Wall Street selloff

The ascendance of DeepSeek, a relatively cheaply made Chinese A.I. app, is sending jitters through Silicon Valley and led to a big selloff on Wall Street. Investors feared that cheaper technology from China may present challenges to American A.I. businesses. There were also American national security concerns. NBC News' Brian Cheung reports.