Interest accrues on a monthly basis, so if you pay it off now you won't accrue the interest on an ongoing basis. In other words - over the life of the loan/mor

Interest accrues on a monthly basis, so if you pay it off now you won't accrue the interest on an ongoing basis. In other words - over the life of the loan/mortgage you will pay $X in principal and $Y in interest. If you suddenly pay the whole thing back, then $Y becomes much smaller. So if you paid $X + $Y in a lump sum then you would receive some money back, is what they are saying. Because you have overpaid on the interest, because that interest never accrued. (not sure whether in this case Citibank paid the full sum of the principal or expected interest or not, but yes, if you did that on your mortgage then you would be entitled to receive some money back)