The U.S. Securities and Exchange Commission building in Washington. (Associated Press/Andrew Harnik)

The nation’s largest public companies are disclosing more information about their political contributions, according to a report released Thursday by the Center for Political Accountability.

S&P 500 companies are moving toward placing restrictions on political spending, devising clear policies to govern spending and enhancing board oversight of company engagement in the political process, the report found.

The report comes at a time when Congress is taking a step in the other direction. Lawmakers on Wednesday passed a short-term spending bill, or continuing resolution, that includes a provision preventing the U.S. Securities and Exchange Commission from requiring public companies to disclose their political spending. The provision was backed by Senate Majority Leader Mitch McConnell (R-Ky.).

The Center for Political Accountability is a nonprofit that promotes transparency in corporate political spending. The annual report is done in conjunction with the Zicklin Center for Business Ethics Research at the University of Pennsylvania’s Wharton business school.

The study rated companies on a scale of zero to 100 based on their policies for disclosing political spending as reported on their corporate websites. The number of companies that scored the highest, with percentages of 91.4 percent or higher, increased from 23 to 35 companies in 2016.

And a growing number of companies addressed “dark money” by adopting or strengthening policies on trade association payments and 501(c)(4) “social welfare” organization contributions.

“The fact that so many companies have embraced greater political disclosure and accountability is a milestone for a super-spending election year,” said Bruce Freed, the center’s president. “Government is gridlocked, but public corporations are not. They’re gradually moving toward sunlight.”

The move toward more transparency is happening at a time when political spending from outside groups is on a dramatic upswing following the Supreme Court’s 2010 decision in Citizens United, which allows corporations and unions to spend unlimited amounts of money in direct advocacy for or against candidates. Wealthy donors are contributing record sums to super PACs in the 2016 election.