Rex Tillerson, President-elect Donald Trump's choice to become secretary of state, disclosed personal wealth of as much as US$400 million ($569.3m), including a Texas cattle and horse ranch, ahead of Senate confirmation hearings expected next week.
Tillerson, who met with members of the Senate Foreign Relations Committee and others this week, promised to sell and restructure assets and resign from outside organizations that might pose a conflict.
The newly retired ExxonMobil chief executive's federal financial disclosure filing shows that he directly holds stock in his former employer worth more than US$50 million that he has pledged to sell within 90 days if he is confirmed as the country's top diplomat.
Tillerson has separately reached a US$180 million retirement agreement with ExxonMobil involving additional stock that would be placed in trust.
He also pledged to recuse himself from any government decisions involving ExxonMobil for one year unless he is specifically authorized to participate.
The State Department sometimes helps energy companies as they seek resources, markets and contacts around the world, and it advises many large corporations.
During the decade that Tillerson led Exxon, the State Department supported some of the oil giant's deals and opposed others, most notably a 2011 agreement with the semi-autonomous Kurdish government in northern Iraq.
That deal, which took US officials by surprise, directly contradicted the US goal of a federal oil deal that would benefit Kurds, Sunnis and Shiites.
The listing of Tillerson's stock and bond holdings shows that he invested in competing energy companies including Total and Royal Dutch Shell while running Exxon.
His portfolio includes American and international businesses ranging from Walmart and Walt Disney to Novartis, Sony and Yum China Holdings, which franchises KFC and other fast-food chains in China.
Federal disclosure requirements call for the value of individual holdings or proceeds to be given as a range, so it is not possible to pinpoint Tillerson's net worth.
Tillerson said he has already resigned from the American Petroleum Institute, a trade group, and would resign from the Boy Scouts of America, the board of Ford's Theater and other organizations.
He pledged to remove himself from business decisions surrounding the ranch in Bartonville, Texas, although he would continue to receive passive income from it.
"I am committed to the highest standards of ethical conduct for government officials," Tillerson wrote in an accompanying letter to a State Department ethics lawyer.
"If confirmed as secretary of state, I will not participate personally and substantially in any particular matter in which I know that I have a financial interest directly and predictably affected by the matter," Tillerson wrote.
The financial disclosure material was sent to the Office of Government Ethics on Wednesday.
Senate Democrats say they still want to see Tillerson's tax returns before holding what Republicans have said could be a two-day hearing January 11 to 12.
Like Trump, Tillerson has refused to provide Congress with his tax returns, promising only "tax return information" upon request, and he has complex business interests from which he must disentangle himself to hold public office.
Tillerson's energy-related work in Russia and his ties to Russian President Vladimir Putin are expected to dominate his confirmation session.
Tillerson's Capitol Hill tour does not appear to be winning new supporters, but it is convincing certain senators that when it comes to sanctions, he may not be as pro-Russia as he seems.
The top Democrat on the Senate Foreign Relations Committee, Ben Cardin of Maryland, said after meeting with Tillerson for over an hour on Wednesday that the businessman was "pretty forthcoming" on sanctions and "understands the importance of sanctions and recognizes that you need to have the ability to get results."
He was referring to US sanctions implemented against Russia in 2014 over its annexation of Crimea and Moscow's support for separatists in eastern Ukraine.
Cardin, the Senate's chief architect of comprehensive new Russia sanctions, has not indicated his support for Tillerson's nomination.
Senator Christopher Coons, with whom Tillerson also met Wednesday, told NPR that he had a productive 90-minute meeting that included tough questions on Russia. Coons said he has not decided how to vote.
Tillerson's close personal and business ties to Russia sparked an early backlash from senators, including a handful of key Republicans, who found alarming his acceptance of the Kremlin's Order of Friendship award in 2013 and his recorded opposition to Ukraine-related Russia sanctions in 2014.
One of those Republicans, Senator John McCain, met with Tillerson on Wednesday, but he did not appear more favorably disposed to the businessman.
When asked whether he would support Tillerson's nomination, McCain told a gathering of reporters "sure - there's also a realistic scenario that pigs fly."