The private equity industry maintained its grip on congressional leaders in 2017, spending exorbitant amounts on lobbying, especially to influence the tax reform bill and maintain the carried interest deduction, FOX Business has learned.

At least six private equity groups attempted to sway congressional lawmakers as they put together the tax reform bill, also known as the Tax Cuts and Jobs Act, and other major pieces of legislation throughout the past year. More than $1 million was spent on lobbying by the PE industry, including by their powerful lobbying arm, the American Investment Council (AIC), which dished out over $600,000, as well as one of the biggest firms in the United States, the Carlyle Group, according to a list distributed by the Center for Responsive Politics.

“The private equity industry, like all other U.S. businesses, was watching the tax reform process very closely. As the industry trade association, the American Investment Council was engaged throughout the tax reform debate. We advocated for a pro-growth bill that would support long-term investing,” Laura Christof, an AIC spokeswoman told FOX Business.

“While the bill requires some trade-offs from all industries – including private equity – we believe it will help our industry continue to provide long-term returns for pension funds, endowments, and other institutional investors that rely on private equity for strong performance,” she added.

A spokesman for the Carlyle Group declined to comment.

Smaller investment firms lobbying congress included Macquarie Infrastructure and Real Assets Inc., Main Street Capital Corp. and Leonard Green & Partners LP according to lobbying disclosure reports reviewed by FOX Business. The sixth group was the Institutional Limited Partners Association, an organization that provides research to private equity executives. None of these smaller investment firms returned requests for comment.

The newly released documents show the issues each company was trying to focus on as they started spending lobbying fees, with one of the top priorities clearly being to retain the private equity businesses coveted loophole known as carried interest.

The provision let’s private equity and hedge funds take some of their funds’ profits as personal income but only pay the relatively low long-term capital gains tax on it. Without that provision, they would have to pay a higher personal income tax rate of 37 percent. Cumulatively, this loophole saves these firms around $2 billion a year.

Lawmakers on both sides of the aisle have long railed against the provision as a benefit for the rich, and there were continued calls that went as high up as President Donald Trump for its removal. During the 2016 presidential campaign, then-candidate Trump said he would end the deduction for everybody during his populist push to win the White House while noting that average families pay a higher income tax rate than executives from this industry.