The credit union lobby is pushing the Senate for a quick vote on legislation easing membership limits.
But Senate Republican leaders are expected to wait until lawmakers return from the Memorial Day recess.
"The message from the majority leader's office was not optimistic," said Scott Sutherland, a spokesman for the Credit Union National Association. "June, July looks better."
"We are planning all the contacts and grass-roots activity we can muster during the Memorial Day break," he said.
The Senate Banking Committee approved a bill April 30 that is slightly tougher than the version the House passed earlier in the month by a landslide 411-to-8 vote. But both measures would let an occupation-based credit union serve any unrelated company with fewer than 3,000 employees.
Though the banking lobby will try to stall the bill and get some changes, American Bankers Association president William T. McConnell conceded defeat Tuesday.
"It would be very easy to get discouraged," he said in a speech before the Pennsylvania Bankers Association's annual meeting in Baltimore. But Mr. McConnell vowed the industry would return to fight another day, bringing more lawsuits and trying to persuade lawmakers to tax credit unions.
"We can always come back," he said. "Even politicians can do the right thing."