Lawyers representing Renaissance Technologies, the $97 billion hedge fund that until last week was run by conservative mega-donor and Trump-backer Robert Mercer, were scheduled to meet with the IRS Tuesday in New York to discuss the estimated $7 billion the fund owes the U.S. government. That meeting, first reported by Bloomberg, came just days before President Trump is scheduled to install an interim head at the IRS who spent a decade as a senior executive at an accounting firm that paid $123 million to avoid criminal prosecution for devising tax avoidance schemes.

Mercer spent at least $22.5 million supporting conservative candidates in the 2016, while backing analytics company Cambridge Analytica, which helped the Trump campaign target voters. He also reportedly invested $10 million in Breitbart News, is helping the president with his legal bills, bankrolled alt-right provocateur Milo Yiannopoulos and advised the Trump campaign, which included using his influence to install Steve Bannon and Kellyanne Conway, Mercer family favorites, in important campaign posts. Last week, Mercer stepped down as co-CEO of Renaissance, which runs a fund that has been called the “perhaps the world’s greatest money making machine.” In a resignation letter to Renaissance employees, Mercer said he would continue working at the firm as a member of the technical staff. He also said he had sold his stake in Breitbart to his daughters for “personal reasons.”

Renaissance has been engaged in a longstanding dispute with the IRS over the use of what are called “basket options”: complicated financial structures that allow hedge funds to treat, or critics say, disguise, short-term financial transactions as long-term investments. This allows funds like Renaissance to pay the capital gains rate (20 percent) on those transactions, instead of treating them as income, and subjecting them to the corresponding income tax rate, which is nearly 40 percent.

The IRS has not commented on how much in unpaid taxes it is seeking from Renaissance, but in 2014 the Senate Permanent Subcommittee on Investigations issued a report that called Renaissance “the largest basket option user,” and estimated the firm avoided $6.8 billion in taxes.

While it’s unclear just how much help Mercer, a computer scientist and staunch libertarian, can expect from the administration in his company’s dispute with the IRS, Trump’s pick to run the agency, David Kautter, will assume the role of acting IRS commissioner next week without Senate confirmation. Kautter worked at accounting giant Ernst & Young for 18 years, a stint that included serving as the firm’s director of national tax from 2000 to 2010.

While Kautter was at Ernst, the firm developed schemes to help clients avoid paying the amount they owed to the IRS. Between 1999 and 2002, Ernst developed tax shelter products for 200 wealthy clients that helped hide $2 billion in tax liabilities, according to a 2013 Justice Department press release describing the department’s $123 million agreement with Ernst. Kautter was not implicated in the tax dodge schemes. Four of those involved were sentenced to between 20 and 36 months in prison, before two of the sentences were overturned.

In August, the Senate Finance Committee confirmed Kautter as assistant treasury secretary for tax policy in a 26-0 vote. During his confirmation hearings, Kautter said he “should have been more active” in uncovering the illegal schemes, the Intercept reported. Kautter was included in email chains at Ernst regarding the tax avoidance efforts, according to The Intercept, but told the Senate committee that the “the firm set up a separate reporting structure with respect to tax shelters” that did not include his office.

Since Mercer became co-CEO in 2010, the same year the IRS issued its initial warning on “basket options,” Renaissance spent $3.5 million lobbying Congress and the treasury department on tax issues. Before 2010, Renaissance spent a total of just $780,000 on lobbying dating back to 2001, according to federal lobbying records.

Renaissance founder James Simons was a major Hillary Clinton donor in 2016. Simons stepped down as CEO in 2010, but Bloomberg reported Tuesday that Simons pressured Mercer to step back from a leadership role at the firm, citing sources that said Simons believed Mercer’s political association with alt-right figures like Bannon and Yiannopoulos was hurting morale at the hedge fund.