Rex Tillerson, the former chairman and chief executive officer of Exxon Mobil, smiled during his testimony before a Senate Foreign Relations Committee confirmation hearing on his nomination for secretary of state in Washington, D.C., Jan. 11, 2017. Reuters

President-elect Donald Trump is on track for the wealthiest cabinet in history, and his choice for secretary of state, Rex Tillerson, might be the one who stands out among the bunch.

A mid-December report by NBC News pegged the former Exxon Mobil chief executive and chairman’s net worth at about $150 million. But a 38-page financial disclosure form from the Office of Government Ethics revealed Tillerson's assets to be about triple that estimate.

Tillerson’s interests in Exxon, which he plans to divest in before entering office, totaled about $300 million. In a nine-page letter accompanying the financial disclosure, addressed to State Department Ethics Officer Katherine McManus, he listed another 156 companies from which he’d cut financial ties—assets the Wall Street Journal calculated were worth between $50 million and $200 million.

About a week before Tillerson’s confirmation hearing began, Exxon announced he would receive cash in place of 2 million shares of the company that he would’ve received over the next 10 years as part of a plan for his retirement. Exxon had announced the deal in mid-December.

Tillerson’s net loss in compensation as a result of the detachment from Exxon, where he’s worked since graduating from the University of Texas in 1975, will be about $7 million, according to the company.

Tillerson didn’t amass all of his wealth from dividends. His salary, which ranked 29th on the New York Times’ list of highest-paid CEOs of 2016, was $24.3 million—or, as the Washington Post put it, 500 times the median U.S. household income.

Meanwhile, Tillerson’s exact net worth is difficult to calculate without his tax returns, something Democrats have pushed for him to make public. However, the Senate Foreign Relations Committee does not require that he provide them.