By Che Pan and Casey Hall BEIJING/SHANGHAI (Reuters) -Demand in China has begun surging for a business that, in theory, shouldn't exist: the repair of advanced Nvidia artificial intelligence chipsets that the U.

In the three months following tightened U.S. export controls under the Trump administration, at least $1 billion worth of Nvidia’s advanced artificial intelligence (AI) chips, primarily the B200 model, were smuggled into China, according to a Financial Times report.

Nvidia has only just been allowed to recommence sales of its H20 AI chipset, which has been specifically developed for China to comply with U.S. restrictions.