WASHINGTON ― The Treasury Department has given congressional Republicans sensitive financial information related to Hunter Biden after having refused to give Democrats President Donald Trump’s tax returns.

Yahoo News first reported Thursday that the Treasury Department handed over highly confidential information in response to a November request from Senate Finance Committee Chairman Chuck Grassley (R-Iowa) and Homeland Security Committee Chairman Ron Johnson (R-Wis.) for suspicious activity reports filed with the department by financial institutions.

Last year, Treasury Secretary Steve Mnuchin blocked a Democratic request for the president’s tax filings, saying Democrats had no legitimate legislative purpose for seeking the documents.

“The legal implications of this request could affect protections for all Americans against politically-motivated disclosures of personal tax information, regardless of which party is in power,” Mnuchin said in an April 2019 letter.

Apparently, that same standard did not apply when it came to non-tax financial information that may pertain to the son of former Vice President Joe Biden, a Trump political rival.

“The administration told House Democrats to go pound sand when their oversight authority was mandatory while voluntarily cooperating with the Senate Republicans’ sideshow at lightning speed,” Ashley Schapitl, a spokeswoman for Sen. Ron Wyden (D-Ore.), the highest-ranking Democrat on the Finance Committee, said in a statement.

Senate Republicans are investigating Hunter Biden as part of an inquiry designed to bolster Trump’s unfounded claim that Joe Biden used the vice presidency to benefit his son, who served on the board of a Ukrainian energy company while his father was involved in setting U.S. foreign policy in Eastern Europe.

For [Treasury] to go willy-nilly handing out financial information of private citizens … is simply outrageous. Steve Rosenthal, Urban-Brookings Tax Policy Center

The inquiry, which includes at least a half dozen records requests to various organizations and executive branch agencies, has proceeded since fall with relatively little notice. It picks up where Trump left off last summer when he asked Ukrainian President Volodymyr Zelensky to investigate whether Biden had improperly recommended the firing of a Ukrainian prosecutor.

Zelensky never followed through because Democrats learned of the scheme from a whistleblower report, which launched their impeachment inquiry and prompted the White House to release a secret hold on military assistance to Ukraine. The House impeached Trump on abuse of power and obstruction of Congress charges in December.

In the Senate trial last month, the president’s lawyers said Hunter Biden’s board membership created the appearance of a conflict of interest, but they stopped short of alleging any actual illegality. As the Senate Republicans’ records requests show, the quest for corroboration continues.

In their letter seeking suspicious activity reports related to Hunter Biden and various associates, Republicans cited an internal Senate rule authorizing the Senate Committee on Homeland Security and Governmental Affairs to investigate the effectiveness of “all agencies and departments” of the federal government. Financial institutions are required to file suspicious activity reports with the Treasury Department if they reasonably suspect customer transactions may be connected to money laundering.

Democrats based their request for Trump’s tax records on a federal tax disclosure law granting congressional committees access to private tax information by request. Mnuchin and the Justice Department claimed that Democrats only wanted to embarrass the president, so they refused to comply. Now the request is tied up in court.

It’s hypocritical for the Treasury Department to stonewall Democrats’ request while granting Republicans access to material on Hunter Biden, said Steve Rosenthal, a senior fellow at the Urban-Brookings Tax Policy Center. He said it’s hard to see what legislative purpose Republicans are after with regard to Hunter Biden.

“For [Treasury] to go willy-nilly handing out financial information of private citizens… is simply outrageous,” Rosenthal said.

Alex Wong via Getty Images Sen. Chuck Grassley (R-Iowa) is one of the Senate leaders who has requested information about Hunter Biden from the Treasury Department.

A spokesman for Grassley wouldn’t say if the Finance Committee is also seeking Biden’s tax returns. The committee generally doesn’t disclose whether it has sought someone’s private tax information; Grassley has used the tax disclosure law to obtain the returns of tax-exempt organizations, such as nonprofit hospitals, and to investigate ACORN, an organization that registered low-income voters, who tend to be Democrats.

The Treasury Department declined to comment.

CORRECTION: This article previously misidentified Wyden’s party affiliation.