Jensen Huang has resigned as president and chief executive of Nvidia, the company said on Thursday, ending a 33-year run in which he built the chipmaker he co-founded in 1993 into the world's most valuable artificial intelligence company.

Nvidia said its board accepted Huang's resignation on Wednesday, with the departure effective immediately. Chief Financial Officer Colette Kress will serve as interim chief executive while keeping her finance role, and the board has begun a search for a permanent successor that will consider internal and external candidates. The board also appointed Harvey Jones, a former chief executive of Synopsys, as its first-ever chair of the board.

Huang's exit follows weeks of mounting pressure. On Sunday, November 8, he admitted in a memo to staff that he had an extramarital affair with Alice Huang, a former executive at Singapore-based data centre firm Megaspeed whom U.S. officials reportedly suspect of spying for China. On Wednesday, fresh reports said he had also had a relationship with a married senior company executive who reported to him. The board opened an independent investigation on Sunday into whether Huang had been the target of a foreign intelligence effort.

Nvidia's announcement gave no reason for Huang's departure, and the company said its operations, customer commitments and product roadmap would continue without interruption. The board thanked Huang for his "profound" and "immeasurable" contributions to the company and the industry.

Shares in Nvidia fell more than 10 percent in premarket trading on Thursday, and the stock was already down more than 20 percent over the past month. Nvidia will still report its fiscal third-quarter results on Tuesday, November 17, as planned.