Which mortgage privilege allows a borrower to make additional payments without incurring fees?

The concept of pre-payment refers specifically to the ability of a borrower to make additional payments on their mortgage without facing penalties or fees. This flexibility allows borrowers to pay down their principal balance faster, which can lead to reduced interest costs over the life of the loan. It is a valuable feature for those who may come into extra funds or want to pay off their mortgage earlier than the original term outlined.

Other terms mentioned, like portability, refer to transferring a mortgage to a new property, cash back often involves getting funds at closing that are based on the loan amount, and expendability is not a recognized term in this context of mortgage privileges. Hence, pre-payment is the clearly defined privilege that allows for additional payments without incurring additional costs, making it the correct choice.