Nvidia CEO Jensen Huang resigned on Thursday following reports of his extramarital affairs with a Chinese businesswoman suspected of spying for Beijing, raising concerns over US national security. The company appointed its Executive Vice President and Chief Financial Officer Colette Kress as interim CEO.

Nvidia's board met to discuss Huang's future after reports emerged of his relationship with Alice Huang, also known as Huang Le, a former senior executive of Singapore-based Megaspeed, which has a partnership with Nvidia. The media also reported that Huang had an affair with another Nvidia executive who reported to him.

Nvidia shares plunged 14% on Thursday, dragging down technology stocks and contributing to a 0.7% decline in the S&P 500 and a 1.5% drop in the Nasdaq. The Dow gained 127 points.

Singapore authorities said they had barred Alice Huang from re-entering the country following an investigation into suspected false declarations involving server purchases and exports to Malaysia. Police investigated her for possible offences, not espionage, and found insufficient evidence to prosecute her. However, she received a stern warning.

Megaspeed Chairman and CEO Tan Yong Pong pledged cooperation with the US government over potential national security concerns. Nvidia said it had no reason to believe its secrets or national security had been compromised.

Technology analyst Dan Ives said Huang's departure was necessary but maintained that Nvidia remained two to three years ahead of its nearest competitor. Kress pledged to build on the foundation Huang established over 33 years. Before joining Nvidia in 2013, she worked at Cisco, Microsoft and Texas Instruments.

China denied allegations of attempting to influence Huang, who had lobbied Washington to ease restrictions on chip sales to China. In January, US President Donald Trump approved Nvidia's sale of H200 chips to China.