Joon Kim has taken down mobsters, pursued a congressman, and investigated sexual harassment claims that toppled a New York governor. His latest assignment will decide the fate of a $4 trillion dollar company the global economy depends on.

The former acting US Attorney for the Southern District of New York was tapped to investigate whether Nvidia CEO Jensen Huang was the target of a Chinese espionage campaign, following Huang’s bombshell admission Sunday that the chief executive had an extramarital affair with a woman alleged to be a Chinese spy.

Kim, a 55-year-old prosecutor who joined Wachtell Lipton last month, will lead an internal probe overseen by a committee of independent directors, into whether Nvidia’s Huang compromised trade secrets — or, more pressingly, the US’ national security interests. The company has said it has confidence in its CEO and has “no reason to believe that either national security or Nvidia secrets were compromised.” A spokesperson for Wachtell declined to comment on the firm’s and Kim’s behalf.

Shares in Nvidia have dropped 10% since Huang’s admission, knocking $500 billion off the company’s market value and stoking worries about the future of a company that underpins an AI financing buildout that has ensnared most of the global financial system. It comes against a fraught national security backdrop in which US officials have been warning for months of foreign influence campaigns and corporate espionage.

A tangled web

Huang, a close confidant of US President Donald Trump, has pushed Nvidia to take stakes in hundreds of companies across the AI boom it supplies. The company has also entered into billions of dollars worth of financing deals up and down Wall Street. 

Even Kim’s own employer, Wachtell Lipton, is not immune: OpenAI is one of Wachtell’s highest-profile clients, and the law firm’s M&A advisors are working on the company’s pending IPO, according to people familiar with the matter. Nvidia is a major OpenAI investor and the primary supplier of the chips that underpin the data centers (which Nvidia also finances) that power OpenAI’s models.

Corporate probes can range from window dressing to essentially prosecutorial in nature, and Nvidia has 4 trillion reasons to limit its damage. It’s unclear how far Nvidia’s board will let Kim roam, but the board has already drummed up corporate governance concerns: The unusually long-tenured board lacks the experience and stature typically found at companies as large as Nvidia’s and has let Huang run the company with no clear successor and more than 50 direct reports.

Mob bosses

Kim began his career at New York’s Southern District more than two decades ago, working in the organized crime unit before leaving for Cleary Gottlieb in 2006. The son of a South Korean diplomat, Kim traveled around the world, including in Jordan and the UK.

In his first stint as a federal prosecutor, Kim took on mob boss John “Junior” Gotti in a federal racketeering trial, trying him for the kidnapping of future New York mayoral candidate Curtis Sliwa. “His entire adult life, John Jr. has thought himself special, entitled to everything, accountable for nothing,” Kim said at the time.

His former colleagues describe Kim as dogged, citing his time at the Southern District in 2013, under Attorney Preet Bharara, where Kim pursued a successful case against disgraced former Congressman Anthony Weiner and briefly ran the Southern District after Trump fired Bharara.

Kim returned to Cleary in 2018, where he led a number of internal investigations into allegations of executive wrongdoing at large corporations, including Nissan Motors’ probe into former CEO Carlos Ghosn. But among his most defining cases was New York Attorney General Letitia James’ investigation into sexual harassment allegations against then-Governor Andrew Cuomo, which led to his 2021 resignation. Cuomo’s office was “rife with bullying, fear and intimidation,” Kim said when announcing his findings.

A sensitive assignment

Before Sunday, Huang and spokespeople for the company had publicly denied that the Nvidia CEO had an affair with Alice Huang. The company abruptly changed tack on Sunday, when Huang wrote a letter to employees admitting to the affair and announcing a plan to initiate an independent probe.

The company had assembled an independent committee to oversee the investigation and was on Sunday leaning toward tapping former Cooley CEO Stephen Neal, the Financial Times reported and Semafor can confirm. Some Nvidia directors also suggested tapping Cooley to run the independent probe, other people familiar with the matter said. Cooley is Nvidia’s longtime outside counsel and would have exposed the company to criticism that the probe wasn’t independent, especially since Cooley is best known for its tech and IP practices, and isn’t considered by white-shoe lawyers to have a top-tier white-collar investigations practice.

Nvidia declined to comment on either the nature of the independent committee or on whether directors considered tapping Cooley.