Nvidia (NVDA) stock faced growing pressure on Monday morning after the chipmaker's board launched an investigation into CEO Jensen Huang's extramarital affair, which is believed to have been with alleged Chinese spy Alice Huang.

"I was unfaithful to my wife. My actions hurt her and our children. There is no excuse for what I did. I am deeply sorry," Huang wrote in a memo to employees.

Given the size and importance of Nvidia in the stock market today, the revelation marks one of the biggest CEO-personal conduct scandals in history. It also highlights Nvidia's key-person risk and uncertain succession plan as questions swirl about whether the board will ask Huang to step down.

The news has drawn immediate and varied reactions from leaders ranging from the US president to other CEOs. President Trump stood by Huang, calling him "an honorable guy," but other members of the president's party are expected to put more scrutiny on the company.

In a statement on Sunday, Nvidia's board said it has "no reason to believe that either national security or Nvidia secrets were compromised."

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