For three decades Nvidia has been inseparable from its co-founder Jensen Huang, and Huang from the chipmaker whose processors power almost every major artificial intelligence system. This week he is also the subject of two investigations: one ordered by his own board, and one that President Donald Trump says the FBI is conducting.

It all began with a series of New York Times articles. According to the paper, American intelligence agencies concluded that a Chinese entrepreneur who had grown close to Huang was working on behalf of Beijing’s foremost intelligence service. The woman, Alice Huang, who is not related to him, spent part of 2023 as a senior executive at Megaspeed, a Singapore data-centre company that bought billions of dollars’ worth of Nvidia hardware and is being examined by Singaporean authorities over suspected evasion of US export rules. Her whereabouts are not known.

In a Sunday message to employees, the 63-year-old admitted to an extramarital relationship and said sorry to his wife and children, while pledging to cooperate fully with any inquiry. Nvidia’s directors then announced a review led by independent board members with outside counsel. So far, the directors said, there is no sign that trade secrets leaked or that American security suffered harm, and they continue to back their chief.

Trump, who counts Huang among his closest allies in the tech world, said he had asked him directly whether he knew the woman was a spy. According to the president, Huang said he had no idea, and Trump added that he believed him. China’s foreign ministry dismissed the espionage claims as groundless smears.

Investors were less relaxed. Nvidia stock ended Monday down about 4.3 percent on a day when rival chipmakers rallied. Huang holds a stake of roughly 3.5 percent and nobody has been publicly lined up to succeed him, which gives the board’s inquiry unusual weight over a company worth about $4.5 trillion.