The U.S. Commerce Department is looking into whether DeepSeek – the Chinese company whose AI model’s performance rocked the tech world – has been using U.S. chips that are not allowed to be shipped to China, a person familiar with the matter said. China’s DeepSeek last week launched a free assistant it says uses less data at a fraction of the cost of U.S. models. Within days, it became the most downloaded app in Apple’s App Store and stirred concerns about United States’ lead in AI, sparking a rout that wiped around $1 trillion off U.S. technology stocks. Current restrictions...