NVIDIA is facing a crisis at the very top.

CEO Jensen Huang admitted in an email to employees on Sunday, November 8, that he was unfaithful to his wife, taking "full responsibility". He did not name the woman or give details of the relationship.

The woman has been identified as Alice Huang, a Chinese businesswoman and former executive of Singapore-based Megaspeed International. The New York Times reported last month that US authorities investigated her and concluded she was a Chinese intelligence asset passing information to Beijing. These are reported allegations only — nothing has been proven, and there is no established evidence that Nvidia's secrets were passed on or compromised.

Nvidia's board announced on November 8 an independent investigation, overseen by independent directors and outside legal counsel. Huang has agreed to cooperate. Nvidia said it had "no reason to believe" its secrets or US national security were compromised.

President Donald Trump confirmed on Monday, November 9, that the FBI is looking into the matter. He said he spoke to Huang, who told him he had no idea the woman was a spy — and Trump said he believes him.

The market reacted sharply. Nvidia shares fell 4.27% on Monday, closing at $178.67 and wiping around $190 billion off the company's market value.

A shareholder class action was also filed on November 9 in federal court in San Jose, alleging Nvidia and Huang misled shareholders, according to Fortune India.

China has rejected the espionage allegations as a "smear".