We have been recently informed at our masjid that Ayatollah Sistani has changed his ruling on Khums for those with debts. The change being – if a person is in debt for a necessity (such as a home loan), that person does not have to pay khums on any savings that is below the total debt amount. Only once your savings exceeds the debt amount, only that excess is liable to khums.

I live with my family and we have a mortgage. The mortgage is not legally in my name, but I contribute to the mortgage from my salary fortnightly. Does this mean I also consider this mortgage (debt) as my debt and I am not to pay khums on any saving below the debt amount? Or is the mortgage not considered my debt because it is not legally under my name?

Yes indeed the new ruling is correct. However, it does not apply to you in this situation since you not legally binding on you. The responsibility is on the legal owner of the house