Curtis J. Mahoney, a Williams & Connolly partner who is the Trump administration's pick for a deputy U.S. trade representative post, reported $833,000 in partnership income from the Washington firm, according to documents the U.S. government ethics office publicly released Tuesday.

The disclosure offers a rare look inside the storied Washington partnership, which is known as much for its loyalty among partners—who almost never leave or join from rival firms—as it is for its confidentiality regarding finances.

Mahoney, who goes by C.J., joined Williams & Connolly in November 2008 and was promoted to partner two years ago. He specializes in international disputes and arbitration. President Donald Trump picked him for deputy U.S. trade representative overseeing investment, services, labor, environment, Africa, China and the Western Hemisphere. The office reportedly is expected to bring an intellectual property trade case against China soon.

Mahoney reported he will receive “a pro rata share of distributable net earnings as a partner calculated as of the day I withdraw from the firm.” He identified his anticipated partnership share at between $500,000 and $1 million.

The financial disclosure, required for certain political appointees, also provided a fuller glimpse of Mahoney's work at the firm. Mahoney identified clients, including 21st Century Fox, News Corp., Merck & Co., Samsung Electronics America Inc. and the Carlyle Group. He provided legal services to the U.S. Chamber of Commerce and to the law firm Hunton & Williams. Mahoney represented the firm as an interested party in a defamation case in Maryland federal district court. Separately, in 2012, Mahoney was on the legal team—with Williams & Connolly's Emmet Flood—that represented the Koch brothers in a suit against the Cato Institute.

In his disclosure, Mahoney cited a confidentiality provision in D.C. attorney-ethics rules in declining to identify five clients. He provided legal services to a technology company and to a U.S. public official who are both subject to a non-public U.S. Justice Department investigation. Mahoney further said two clients—a U.S. private equity executive and a Brazilian businessman—are involved in confidential arbitration proceedings. Mahoney declined to identify an unnamed Roman Catholic diocese that is grappling with what he described as “alleged clerical abuse of minors.”

Mahoney declined to comment Tuesday.

Williams & Connolly last week found itself amid a swirl of reports—and a denial—about merger talks with Quinn Emanuel Urquhart & Sullivan. Williams & Connolly said there no deal was in the works. “While Quinn Emanuel is an excellent law firm, we are happy just the way we are. We have no plans to merge with them or any other law firm,” Dane Butswinkas, chairman of Williams & Connolly, said in a statement last week.

Williams & Connolly reports that it has about 300 lawyers, all in Washington. A former seven-year Williams & Connolly associate, Brian Rabbitt, joined the White House counsel's office earlier this year. The firm, according to a Yahoo News report in June, was among several in Washington that turned down representing Trump amid the ongoing investigation of Russia's interference in the 2016 presidential election.

Greg Craig, the Obama administration's first White House counsel, reported making $1.7 million at Williams & Connolly in 2008. Two then-associates who joined Craig—Jonathan Kravis and Christian Weideman—reported earning $220,000 and $310,000, respectively, that year. This year's Am Law 100 survey identified Williams & Connolly's profits per partner at $1.59 million.

Mahoney said he would withdraw from the firm's partnership on his confirmation and, within 60 days, receive his final partnership share distribution and a refund of his capital account. “W&C will calculate the amount of these payments as of the date of my withdrawal. I will not receive a bonus,” Mahoney wrote in his ethics agreement. He estimated the value of his capital account between $50,000 and $100,000.

Mahoney is a 2006 Yale Law School graduate who clerked for Judge Alex Kozinski of the U.S. Court of Appeals for the Ninth Circuit and later for Justice Anthony Kennedy during the 2007-08 term. That term, Kennedy wrote the majority ruling in Boumediene v. Bush, which said Guantánamo Bay detainees can use federal district courts to challenge the lawfulness of their detention. A Kansas native, Mahoney was scheduled to speak in May in Kansas City, Missouri, about the confirmation of Neil Gorsuch to the U.S. Supreme Court.

Federal campaign records show Mahoney donated to the U.S. Senate campaign of Tom Cotton, an Arkansas Republican and a Harvard Law School graduate who previously worked at Gibson, Dunn & Crutcher and Cooper & Kirk. The election database does not show any contributions from Mahoney for any candidate in the 2016 presidential election. Mahoney donated $100 last year to the campaign of Josh Hawley, the Republican attorney general for Missouri.

Mahoney would join the office of Robert Lighthizer, a former Skadden, Arps, Slate, Meagher & Flom partner who was confirmed this year as the U.S. trade representative. Another Skadden partner, Jeffrey Gerrish, is up for a deputy slot in that office. Trump in March appointed Stephen Vaughn, a King & Spalding partner, as the general counsel to the U.S. trade representative. Vaughn had joined the firm in 2016 from Skadden.

Katelyn Polantz in Washington contributed to this report.

The disclosure offers a rare look inside the storied Washington partnership, which is known as much for its loyalty among partners—who almost never leave or join from rival firms—as it is for its confidentiality regarding finances.

Mahoney, who goes by C.J., joined Williams & Connolly in November 2008 and was promoted to partner two years ago. He specializes in international disputes and arbitration. President Donald Trump picked him for deputy U.S. trade representative overseeing investment, services, labor, environment, Africa, China and the Western Hemisphere. The office reportedly is expected to bring an intellectual property trade case against China soon.

Mahoney reported he will receive “a pro rata share of distributable net earnings as a partner calculated as of the day I withdraw from the firm.” He identified his anticipated partnership share at between $500,000 and $1 million.

The financial disclosure, required for certain political appointees, also provided a fuller glimpse of Mahoney's work at the firm. Mahoney identified clients, including 21st Century Fox, News Corp., Merck & Co., Samsung Electronics America Inc. and the Carlyle Group. He provided legal services to the U.S. Chamber of Commerce and to the law firm Hunton & Williams. Mahoney represented the firm as an interested party in a defamation case in Maryland federal district court. Separately, in 2012, Mahoney was on the legal team—with Williams & Connolly's Emmet Flood—that represented the Koch brothers in a suit against the Cato Institute.

In his disclosure, Mahoney cited a confidentiality provision in D.C. attorney-ethics rules in declining to identify five clients. He provided legal services to a technology company and to a U.S. public official who are both subject to a non-public U.S. Justice Department investigation. Mahoney further said two clients—a U.S. private equity executive and a Brazilian businessman—are involved in confidential arbitration proceedings. Mahoney declined to identify an unnamed Roman Catholic diocese that is grappling with what he described as “alleged clerical abuse of minors.”

Mahoney declined to comment Tuesday.

Williams & Connolly last week found itself amid a swirl of reports—and a denial—about merger talks with Quinn Emanuel Urquhart & Sullivan. Williams & Connolly said there no deal was in the works. “While Quinn Emanuel is an excellent law firm, we are happy just the way we are. We have no plans to merge with them or any other law firm,” Dane Butswinkas, chairman of Williams & Connolly, said in a statement last week.

Williams & Connolly reports that it has about 300 lawyers, all in Washington. A former seven-year Williams & Connolly associate, Brian Rabbitt, joined the White House counsel's office earlier this year. The firm, according to a Yahoo News report in June, was among several in Washington that turned down representing Trump amid the ongoing investigation of Russia's interference in the 2016 presidential election.

Greg Craig, the Obama administration's first White House counsel, reported making $1.7 million at Williams & Connolly in 2008. Two then-associates who joined Craig—Jonathan Kravis and Christian Weideman—reported earning $220,000 and $310,000, respectively, that year. This year's Am Law 100 survey identified Williams & Connolly's profits per partner at $1.59 million.

Mahoney said he would withdraw from the firm's partnership on his confirmation and, within 60 days, receive his final partnership share distribution and a refund of his capital account. “W&C will calculate the amount of these payments as of the date of my withdrawal. I will not receive a bonus,” Mahoney wrote in his ethics agreement. He estimated the value of his capital account between $50,000 and $100,000.

Mahoney is a 2006 Yale Law School graduate who clerked for Judge Alex Kozinski of the U.S. Court of Appeals for the Ninth Circuit and later for Justice Anthony Kennedy during the 2007-08 term. That term, Kennedy wrote the majority ruling in Boumediene v. Bush, which said Guantánamo Bay detainees can use federal district courts to challenge the lawfulness of their detention. A Kansas native, Mahoney was scheduled to speak in May in Kansas City, Missouri, about the confirmation of Neil Gorsuch to the U.S. Supreme Court.

Federal campaign records show Mahoney donated to the U.S. Senate campaign of Tom Cotton, an Arkansas Republican and a Harvard Law School graduate who previously worked at Gibson, Dunn & Crutcher and Cooper & Kirk. The election database does not show any contributions from Mahoney for any candidate in the 2016 presidential election. Mahoney donated $100 last year to the campaign of Josh Hawley, the Republican attorney general for Missouri.

Mahoney would join the office of Robert Lighthizer, a former Skadden, Arps, Slate, Meagher & Flom partner who was confirmed this year as the U.S. trade representative. Another Skadden partner, Jeffrey Gerrish, is up for a deputy slot in that office. Trump in March appointed Stephen Vaughn, a King & Spalding partner, as the general counsel to the U.S. trade representative. Vaughn had joined the firm in 2016 from Skadden.

Katelyn Polantz in Washington contributed to this report.