A public interest law firm filed a lawsuit Tuesday against the Consumer Financial Protection Bureau for failing to produce documents that showed how the agency decided to ban mandatory arbitration clauses.

The CFPB's arbitration plan is expected to be finalized in early 2017. The controversial plan, released in May, would prohibit banks and other firms from forcing consumers into mandatory arbitration, allowing customers to file class action lawsuits.

The Cause of Action Institute, a nonprofit law firm, filed a far-reaching Freedom of Information Act request in April asking for "all records by or between CFPB employees regarding the arbitration study and/or proposed ban."

The firm said the CFPB withheld 1,877 pages of "responsive records," and challenged the agency's FOIA exemptions. The CFPB denied the firm's appeal last month.

Cause of Action said the CFPB's own arbitration study, released in March 2015, "failed to follow rigorous scientific standards under the Information Quality Act."

Many in the industry have seized upon data from the bureau's arbitration study to show that arbitration is in the public interest, and that the CFPB's findings do not align with the bureau's own proposal.

The CFPB's study found that consumers received an average of $5,389 in arbitration, compared with just $32.25 from class action settlements. The disparity in payouts is being used to challenge the CFPB's arbitration plan.

"To issue a regulation affecting such a vast swath of the economy, and then attempt to conceal the bulk of the documents reflecting how that decision was made from public view, violates the law and the American people's right to know," said John Vecchione, a vice president at Cause of Action.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.