Federal Reserve Chairman Ben Bernanke again told lawmakersThursday that “there are good reasons” to be concerned aboutwhether the exemption for small debit card issuers on the debitinterchange rule could work.

“It's going to affect revenue of small issuers. And it could resultin some smaller banks being less profitable or even failing,"Bernanke told the Senate Banking Committee in response to questionsfrom Sen. Jon Tester (D-Mont.)

The lawmaker is sponsoring legislation that would delay theimplementation of the Federal Reserve’s rule regulating debitinterchange fees by two years while financial regulators, includingthe NCUA, study the issue.

Tester has said he has the 60 votes needed to defeat a likelyfilibuster but hasn’t found a legislative vehicle to attach it to.The Fed has been drafting the rule as a result of the DurbinAmendment to last year’s financial overhaul bill. The amendment wassponsored by Sen. Majority Whip Richard Durbin (D-Ill.)

The Fed issued a draftedrule in December and was supposed to issue a final rule nextmonth but has been delayed in doing so because it is still goingthrough the large number of comments it received on the proposal.The final rule is supposed to take effect in July.

Acording to the proposed rule, the allowable costs forinterchange would be limited to no more than the issuer's allowablecosts divided by the number of electronic debit transactions onwhich the issuer received or charged an interchange transaction feein the calendar year. Or the issuer could receive debit interchangecapped at 12 cents per transaction.