Nvidia’s board said Thursday that Jensen Huang has resigned after 33 years at the company he built, and that CFO Colette Kress will serve as interim CEO.

The decision comes after Nvidia’s board met late Wednesday, following reports that Huang had a relationship with an Nvidia executive.

The CEO was already under scrutiny after reports of an affair with a different woman who was allegedly working as a spy for China, with the board hiring a law firm to investigate.

Shares in the company, a major engine of US economic growth that has powered the AI boom, fell sharply in premarket trading.

The stock is one of the largest in the S&P 500 and other major indexes, and its volatility affects retirement funds across the globe.