Steven Mnuchin, President-elect Trump's pick for Treasury secretary, defended his time in the financial sector at his Senate confirmation hearing on Jan. 19 at the Capitol. (Reuters)

President-elect Donald Trump’s nominee to lead the Treasury Department initially failed to disclose his interests in a Cayman Islands corporation, as well as more than $100 million in personal assets, according to a memo by Democratic staffers on the Senate Finance Committee that was obtained by The Washington Post.

Steven T. Mnuchin faced lawmakers Thursday in a testy confirmation hearing before the Senate Finance Committee. Mnuchin has already come under fire for his management of a California bank accused of aggressively foreclosing on homeowners and discriminating against minorities — charges that he denies. Democrats have also sought to highlight the former Goldman Sachs executive’s deep ties to Wall Street in hopes of undercutting Trump’s populist appeal, and the new details of his financial holdings are likely to provide them more ammunition.

"The reason nominees are allowed to amend their disclosure forms is to ensure that all the information provided is correct," Mnuchin spokeswoman Tara Bradshaw said. "That is why we have provided the appropriate amended forms to the committee."

During his testimony Thursday, Mnuchin said he did not personally benefit from his positions in offshore entities, which he said were set up to serve nonprofits and pensions. He pledged to work with Congress to eliminate such incentives.

“In no way did I use them to avoid U.S. taxes," Mnuchin said. "I can assure you I pay all my taxes as was required.”

According to the memo, Mnuchin submitted answers Dec. 19 to a standard committee questionnaire seeking information about his financial and business interests. At the time, Mnuchin verified that those responses were accurate and complete.

Mnuchin at first failed to disclose his role as director of Dune Capital International, which is incorporated in the Cayman Islands, the document shows. He also holds positions in nine other business entities and three trusts, including one connected to Sears chief executive Edward Lampert, Mnuchin’s former college roommate.

However, Mnuchin had left out $95 million in real estate from his initial disclosures, according to the memo. Those assets included a co-op in New York City and homes in Southampton, New York and Los Angeles. In addition, the memo revealed that Mnuchin possesses about $15 million worth of real estate in Mexico. Also left off was $906,556 in artwork held by his children, the memo said.

According to the memo, Mnuchin characterized the missing information as inadvertent mistakes, and he updated his answers to the committee’s questionnaire on Saturday, less than a week before his hearing.

Mnuchin is just one of the ultra-rich advisers that Trump has picked to fill his Cabinet, which is expected to be the wealthiest in modern American history. Billionaire investor Wilbur Ross is the nominee to lead the Commerce Department, while Education Department nominee Betsy DeVos is the daughter-in-law of Richard DeVos, the co-founder of Amway. Trump’s pick for secretary of state, Rex Tillerson, retired as chief executive of ExxonMobil following his nomination with a retirement package of $180 million.

The nominees’ extensive and complicated financial ties — coupled with the fact that many of them have never served in government — have overwhelmed the government’s ethics office as well as committee staff responsible for vetting them. Delays in paperwork and financial disclosures forced hearings to be delayed for several Cabinet picks, including labor secretary nominee Andrew Puzder, chief executive of CKE Restaurants, which owns burger chains Carl’s Jr. and Hardee’s.

"Mr. Mnuchin’s failure to disclose his Cayman Islands holdings just reeks of the swamp that the President-elect promised to drain on the campaign trail," Sen. Chuck Schumer (D-N.Y.) said in a statement Thursday. "In nominee after nominee, [Republicans are] tolerating a dramatically lower bar for ethical standards, something Washington and America will soon regret.”

Republicans raised similar concerns about outgoing Treasury Secretary Jack Lew during his confirmation in 2013, pointing to his own ties to entities in the Cayman Islands and bonuses received while at Citigroup. Lew was confirmed by the Senate by a wide margin of 71-26 votes.

Word of errors in Mnuchin's disclosure forms comes amid growing ethical issues for other Trump Cabinet nominees that raise questions about their nominations.

On Wednesday, Democratic senators repeatedly questioned Rep. Tom Price (R-Ga.), Trump's choice to lead the Department of Health and Human Services, about personal investments in health-care firms that benefited from legislation that he was pushing at the time.

News reports also revealed that Rep. Mick Mulvaney (R-S.C.), Trump’s nominee to head the Office of Management and Budget, acknowledged during his vetting process that he failed to pay more than $15,000 in state and federal employment taxes for a household employee.

And Commerce Department nominee Wilbur Ross told lawmakers during his confirmation hearing Wednesday that one of the “dozen or so” housekeepers he has hired since 2009 was undocumented. He had only recently discovered the worker's status and fired the individual, he said.

Republicans are still hoping to confirm at least a handful of Trump's nominees on Friday afternoon after his inauguration. There is little opposition to most of Trump's top national security picks, including retired Marine Gen. James Mattis to lead the Pentagon; Rep. Mike Pompeo (R-Kan.) to lead the CIA; and retired Marine Gen. James Kelly to serve as secretary of homeland security.