All Danish “realkredit” morgages are done with bonds, so the “bank” is not loosing money, the buyer of the bond is.

For some loans, on some conditions, the morgage is actually negative, and lender is either paid a quartely price, or the debt is lowered accordingly. (This is for the morgage named F5, with a fixed 5year rate, and when the house has very low debt, then the fee charged, is also lower, as it is based on risk)