The U.S. Senate has only a few days left to repeal Obama-era regulations, so lawmakers’ financial industry donors have been lobbying hard on legislation that could prevent states from offering low-cost retirement savings accounts to millions of workers.

Under the Congressional Review Act (CRA), lawmakers have only a certain amount of time to repeal such regulations passed toward the end of the previous president’s term. In February, the House passed two bills — which invoked the CRA — to reverse Department of Labor regulations permitting cities and states to offer retirement accounts to workers whose employers do not already offer retirement benefits. The Senate passed one of the bills revoking the regulations that help cities, but it has not passed the more far-reaching bill that could shut down retirement savings programs now operated by eight states.

The CRA deadline for the upper chamber is May 9, and groups like the AARP that support the state-based plans expect the repeal measure to be voted on this week.

Read: Wall Street Wins As GOP Votes To Block States From Offering Low-Cost Plans

As the Donald Trump administration vows to have the president sign the repeal measure if it gets to his desk, federal records show that major financial industry power players have been lobbying on the repeal legislation in the first three months of 2017. Eight of the Wall Street firms and trade associations that have been lobbying specifically on the legislation originally led the opposition to the Labor Department regulations when they were first proposed. In the last three election cycles, those eight groups have delivered more than $2.5 million of campaign cash to Senate candidates — many of whom could be voting on the repeal legislation this week.

Proponents of the state-based plans — including unions, retiree groups and state officials — have argued that by providing low-fee voluntary savings plans that do not involve taxpayer contributions, the programs provide a cost-effective retirement benefit for millions of workers who do not already have such benefits.

The financial industry has aggressively opposed those plans in the states; most recently, industry lobbyists successfully killed a state-based retirement proposal in Colorado. The plans have generated such pushback, in part, because they could increase competition for retirement savings services and potentially undercut Wall Street firms that charge workers higher fees for such services.

That Wall Street opposition in the states has lately been replicated in Washington.

For example, the Investment Company Institute, which represents the mutual fund industry, slammed the proposed regulations to allow state-based savings plans in a 2016 letter to regulators. The group argued that the new measures would “grant states the ability to use tools not otherwise available to private-sector employers and retirement plan providers today.”

A year later, the Investment Company Institute listed the repeal legislation among bills it was lobbying on in the first three months of 2017. In the last two election cycles, that group’s political action committee has delivered more than $378,000 to senators and has also donated $120,000 to the Senate fundraising arm of both parties, according to data compiled by the Center for Responsive Politics.

Similarly, the Securities Industry and Financial Markets Association (SIFMA) listed the repeal legislation on disclosure forms documenting $1.7 million worth of lobbying expenditures in the first three months of 2017. The trade association representing financial firms urged regulators to reject the rule because it might reduce business for Wall Street.

“Implementing the type of plan detailed in the proposed rule would add significant costs to the States to operate the program, while simultaneously crowding out the private market, which today provides a wide variety of individual retirement account options,” the group wrote.

SIFMA’s political action committee has given more than $240,000 to Senate candidates in the last two election cycles.

The political action committee of the National Association of Insurance and Financial Advisors has given senate candidates more than $920,000 since the 2012 election cycle. That group has been lobbying on the repeal legislation after it opposed the original rules.

Despite millions of workers not getting retirement benefits through their employers, the group asserted that the regulations are “neither necessary nor an effective solution for promoting retirement planning and security.” The group further asserted that “a vibrant private-sector retirement planning market already exists, which offers a comprehensive array of affordable retirement solutions to individuals and businesses.”

Other groups and corporations that have been lobbying on the repeal bill and that opposed the original regulations include the American Benefits Council, Voya, the Financial Services Roundtable, the Insured Retirement Institute and the National Federation of Independent Business.