With the Senate not meeting this week, a vote on an amendment to delay the implementation of the Federal Reserve's interchange rule won't happen until next week at the earliest.

Senate Majority Leader Harry Reid has said he will allow a vote on the amendment by Sen. Jon Tester (D-Mont.), to delay the implementation by 15 months after lawmakers return from their Memorial Day break. Reid has said he will oppose the measure.

However, it's not clear what legislation the amendment will be attached to. In Senate parlance, they are looking for what in legislative parlance is called an “amendable vehicle.”

Lobbyists for banks and credit unions who have been pushing for the amendment have said the final vote will be close and declined to predict if they have enough votes to  pass it.

Normally the Senate stands in recess during Memorial Day breaks but Republicans declined to agree to recess for fear that President Obama would use it to make a recess appointment of Elizabeth Warren as head of the Consumer Financial Protection Bureau.

Instead, the Senate is meeting in brief pro forma sessions this week and conducting no business.