Nvidia shares have declined after an internal investigation into whether chief executive Jensen Huang had been targeted by a foreign intelligence effort put his future at the artificial intelligence chip maker under scrutiny.
The internal probe followed a US media report that Huang had a close relationship with a Chinese businesswoman who allegedly passed information to authorities in Beijing.
Huang told Nvidia's employees that he had been unfaithful to his wife, without disclosing details of the relationship.
The investigation, announced on Sunday, has put a spotlight on 63-year-old Huang's future given Nvidia's status as the world's most valuable chip maker and his role as the most prolific salesman of the AI boom.
"I support the investigation and will co-operate fully. I love our country and our company. I am committed to protecting NVIDIA and supporting America’s national security," Huang said in an open letter posted on Nvidia's website.
The leather-jacketed Huang enjoys rock-star status worldwide, particularly in Asia, where he often mingles freely with fans, taking selfies and signing autographs for his devoted followers.
He is Nvidia's fifth-largest shareholder with a roughly 3.6 per cent stake, according to LSEG data, and keeps a tight grip on the company through an unusually flat structure in which dozens of executives report directly to him.
But unlike Meta Platforms or SpaceX, Nvidia has no dual-class shares that would give its co-founder majority voting control.
The fallout of the probe extended to South Korea where Madison Huang, Huang's daughter and an Nvidia executive, cancelled a planned visit to Seoul for an Nvidia conference that was set to begin on Monday, according to companies she had been scheduled to meet.
Nvidia's shares pared losses from an eight per cent slide to being down six per cent, extending last week's sell off and pushing the stock to fresh multi-month lows.
At current levels, the chipmaker would lose more than $US280 billion ($A405 billion) in value from its last closing price.
The chip maker said its board has confidence in Huang.
Analysts acknowledged uncertainty around succession but most do not expect the investigation to result in the longtime CEO stepping down.
"The key-person risk is massive since Jensen co-founded Nvidia, built the CUDA ecosystem that underpins its competitive advantage and personally anchors relationships with the largest AI customers and governments," Shay Boloor, chief market strategist at Futurum Equities, said.
The New York Times reported last month that Huang had a relationship with Alice Huang, an unrelated former executive of Singapore-based company Megaspeed, who US authorities investigated and concluded was a Chinese intelligence asset.
"The so-called Chinese spy narrative is purely a groundless accusation, slander and a smear," Chinese foreign ministry spokesman Guo Jiakun told reporters in Beijing.
Alice Huang did not respond to the NYT last month when it first reported her relationship with Huang, and Reuters could not determine her location to seek comment on Monday.
Billionaire investor Bill Ackman, founder of Pershing Square Capital Management, said on X Huang was an "incredible human" but if "indeed this is more than an affair, then it is obviously a real problem".
"I am hoping for a simple affair, not a risk to our national security," he said.
US President Donald Trump said on Sunday he had not spoken to Huang about the allegations, but called him a fine person.
"I hope everything's fine. He's done such an incredible job," he added.
Analysts said a prolonged investigation or internal review could potentially delay Nvidia's investment decisions or product launches, with broader implications for the semiconductor industry.
