The American Bankers Association (ABA) has filed a lawsuit against the National Credit Union Administration over a rule the ABA says would unlawfully expand fields of membership for credit unions.

This latest salvo in the dispute between the banking and credit union industries comes on the heels of the NCUA’s decision to also loosen the business lending cap on credit unions. The Independent Community Bankers of America have challenged that rule in their own lawsuit, which the ABA said it supports and intends to file an amicus brief.

The ABA said in a statement that the rule “disregards Congress’ explicit instruction that community credit unions serve only a single, well-defined local community.” The lawsuit filed Wednesday in the U.S. District Court for the District of Columbia, seeks to overturn the NCUA rule.

The ABA continued to say: “NCUA’s rule is part of a continuing effort by the agency to expand the size of federal credit unions, as shown by a separate NCUA proposal that would quadruple the population limit on community fields of membership to 10 million, which goes well beyond congressional limits. ABA’s lawsuit challenges NCUA’s final rule as contrary to statutory constraints that limit credit unions’ field of membership in order to ensure a ‘meaningful affinity and bond among members.’”

“NCUA’s rule ignores statutory requirements at the expense of taxpayers, small banks and the communities those banks serve,” ABA President and CEO Rob Nichols said in a statement. “ABA has successfully sued NCUA three times on past occasions in which the agency exceeded its congressional authority, and we look forward to challenging their latest violation of the law in federal court.”