here's my take
A decision to retain a leveraged property investment has two aspects which are worth analysing separately.
- Is the property worth retaining.
- Is the loan worth retaining.
The first (is the property worth retaining) should be decided based on the Net Present Value of the property, which will incorporate analysis of the expected rent, expenses, growth rate in rent, market value of the property (i.e. the opportunity cost of not selling it) and the investors required rate of return.
The second - Is the loan worth retaining - can be answered by valuing the loan based on market rates of return and comparing this to the outstanding amount.
Example (highly simplified):
Tracker mortgage at 1.5%
Interest Only (interest payable annually)
20 years
Principal €100K
To value the loan we need to know what rate the owner could borrow for this investment today. Lets say 4.25% (AIB standard variable)
From the perspective of the bank - the loan is annual 20 payments of €1,500 plus a payment of €100,000 in 20 years. The bank would lend today at 4.25%.
The present value of this loan is (i.e. the value of the payments the borrower has to make to repay this loan, expressed in today's terms)
1500/(1.0425) + 1500/ (1.0425)^2 + 1500/ (1.0425)^3.........101,500/(1.0425)^20
the present value of the loan repayments is €63,440. The borrower had the use of €100,000 for which they are paying €63,440 - Even if the property os overvalued by 30% - the optimal decision may still be to retain the property because of the subsidy from the lender.