Practically speaking, there will rarely be a situation where this would be an issue. Either the bank is not a Jewish bank and a Jew is allowed to borrow money from them with interest, or it is a Jewish bank in Israel and they have a Heter Iska to obviate the problem of lending with interest.

But let's say there is a Jewish bank without a Heter Iska and it is lending to Jews. The last Mishnah in Perek Eizehu Neshech (75b) says that not just the borrower and the lender are in violation of Ribis, but even the guarantor on the loan and the witnesses to the loan. The Gemara there says that they have violated the prohibition of "Lo Sesimun Alav Neshech". The Rambam, however, adds "Asur l'Hisasek Bein Loveh u'Malveh" - one is not allowed to be a broker because of the general prohibition of Lifnei Eever - causing a stumbling block to a fellow Jew (see Sha"ch, YD 160:1). I think that a loan officer in a bank would be included in this prohibition.

Kol Tuv,

Yonasan Sigler

This is not a Psak Halachah