What is DeepSeek, and why did it cause the markets and U.S. tech giants to quake? Cade Metz, a technology reporter for The New York Times who writes about artificial intelligence, explains.

Major figures in artificial intelligence (AI) acknowledge the accomplishment of Chinese start-up DeepSeek, but caution against exaggerating the company's success, as the tech industry weighs the implications of the firm's advanced models developed at a fraction of the usual cost.

Tech companies and academics have long wrestled with the risks and rewards of building open source software. But the frenzy around generative artificial intelligence has lent new significance to the debate.