Nvidia has rejected a report that a business contact of chief executive Jensen Huang was suspected by US officials of spying for China.
The report, by the New York Times, centres on an executive at Megaspeed, a Singapore-based data centre company and Nvidia customer.
US intelligence agencies reportedly concluded that the executive had passed information to Beijing, according to the newspaper.
The Times also said Huang had not been formally warned by security officials, despite his close dealings with the executive.
Nvidia responds
Nvidia said Huang meets thousands of customer executives every year and described the relationship as "normal and not unusual".
It said it would expect US authorities to warn it about any business contact that posed a threat.
The company said it had checked chips shipped to Megaspeed and found no evidence they had been illegally sent on to China.
Huang said the executive no longer works for Megaspeed.
President Donald Trump said he supported Huang but that the claims would be looked at closely.
China dismissed the allegations as "groundless speculation".
Shares fall
Nvidia shares closed 4.22% lower at $204.64 after the report, before edging up 0.30% in after-hours trading.
The row adds to Nvidia's existing difficulties in China.
US export controls have already blocked most sales of its advanced AI chips there.
Huang has estimated the Chinese market could have been worth about $50 billion to Nvidia in 2025 if it had stayed open.
Read more about Nvidia
