Hedge fund manager Tom Steyer, who is leading a campaign to impeach Trump, has been pressuring Neal to request the president's tax returns.
Now, the question is likely to get renewed attention because of the House Ways and Means Committee's request to the Internal Revenue Service for six years of Trump's returns - and the huge legal battle that is expected over whether they will be released.
Neal requested Mr. Trump's individual tax returns for the years 2013 to 2018, as well as a statement stating whether the return is or was subject to an audit and, if so, the reasons why. "It seems doubtful that the committee needs all of a President's tax returns to make that determination", Grewal said. "Usually, it's 10, so I guess they're giving up".
In a letter to IRS Commissioner Charles P. Rettig, Massachusetts Rep. Richard Neal said that he wanted to investigate whether the IRS is following its policy of auditing all sitting presidents and vice-president's tax returns.
In this April 2, 2019, photo, House Ways and Means Committee Chairman Richard Neal, D-Mass., arrives for a Democratic Caucus meeting at the Capitol in Washington.
"Democrats say they're interested in the tax returns of all presidents when they're really just interested in one: President Trump", Grassley said, adding, "It's motivated by the Democrats' intense dislike of this President".
Neal's committee initially planned to request only Trump's personal tax returns.
"Weaponizing our nation's tax code by targeting political foes sets a unsafe precedent and weakens Americans privacy right", Rep. Kevin Brady (R-Texas) said.
Democrats Make Good On Threat, Demand Six Years Of Trump Tax Returns
He added that he does not believe the Treasury Secretary or the IRS has to provide Congress with his tax returns so long as he is under audit, as he now claims to be.
Neal told CNN that he believes his request will be fulfilled, though perhaps not without a fight.
Cohen also cast doubt on Trump's statement that he's under audit.
Trump quickly said he was not inclined to share his tax returns.
Pelosi and other Democrats have argued that the tax return request is a matter of necessary congressional oversight of the executive branch and that Democrats are on solid legal ground in making the request.
But in February 2016, Trump appeared to become skittish about releasing his tax returns, arguing he could not disclose his returns, because he was now being audited by the IRS - even though an audit does not prevent a taxpayer from releasing his or her own tax documents.
Every U.S. president since Gerald Ford in the 1970s has voluntarily made his tax returns public.