A multi-currency mortgage is a mortgage loan in a currency other than the local one.
That is, instead of signing a mortgage in euros, the loan is signed in a different currency such as the dollar or the Japanese yen, for example.
In a multi-currency mortgage, the loan installments will vary depending on the interest rate if it is an adjustable-rate mortgage and also on the exchange rate of the currency in which it was signed. In other words, if the exchange rate between the euro and the currency in which the mortgage is contracted rises, so will the installments and the contracted capital in euros.
A multi-currency mortgage is a sophisticated debt instrument that has an additional risk to that of a traditional mortgage.