A portable mortgage allows the borrower to move their mortgage from one property to another without penalty within an early repayment charge period. e.g.: if there are early repayment charges for the first 3 years on your mortgage then if you wanted to move house... A collection of securities or assets of an investor. Within property this will refer to the collection of residential and commercial property or land that a person has invested into in order to obtain a return. When the Purchaser takes over legal control of the premises.