An interest rate rise of 2% would have a negative impact on 89% of landlords, with 53% concluding that the effect would be significant in a survey by the NLA.
A further 8% would be forced to re-evaluate their future as a landlord, with 6% having to reduce their portfolios or leave the private-rented sector completely.
Some 662 landlords participated in the survey.
Almost three quarters of those landlords have at least one mortgage, and of those 47% have at least five BTL mortgages held against their property portfolio.
Under one half of landlords, 49% strongly agree that the market would further benefit from more buy-to-let lenders and greater competition.
David Salusbury, chairman at the NLA, said: “These statistics show how important it is for a landlord expanding their portfolio to construct a sound long-term business plan when considering buy-to-let properties.
“The NLA believes that such properties can be a worthwhile investment and can help ease the current housing crisis by providing a source of much needed housing, but landlords should ensure that they plan for the future and are mindful of any potential increases in BTL interest rates.”
