Portman has become the first building society to announce that it will not approve buy-to-let mortgages for the purchase of property that is less than a year old.
Concerns about buy-to-let valuation have prompted this move by the mortgage lender.
Until the market stabilises, Portman will not offer buy-to-let mortgages to landlords hoping to find a mortgage.
A surplus in newly built properties has been blamed for the apparent lack of resolve in the valuation of property.
"Some developers are now prepared to do deals on price outside of the formal contract," comments development director, Matthew Wyles.
He adds that in these cases, the mortgage lender may be unaware of the actual price being paid and then ends up relying on a valuation, which may in turn be based on "erroneous assumptions".
Portman buy-to-let mortgages will enter the market again once a balance is struck between supply and demand, Mr Wyles said.
Earlier this week, Leeds Building Society has launched a buy-to-let mortgage that it claims is "ideal" for first-time landlords.
The mortgage lender's product development manager, Stuart Fearn, has said it is also an attractive buy-to-let mortgage option for professional landlords who want to remortgage their portfolio onto "a highly competitive discount rate".





