"As landlords move to navigate the changing environment, so too must lenders ensure that their approach to lending is robust."
If an application fails the test, Landbay says it may consider applications using up to 10% of the declared income, subject to a minimum personal income of £100,000.
The lender says the new rates reflect its "ongoing commitment to being fully equipped for the recent PRA changes".
Last week, Landbay announced that it has extended its lending criteria to include first time landlords who do not currently own a residential property, designed to help professional people who are renting to invest in property themselves and get a foot on the housing ladder.
Paul Brett, Managing Director of Intermediaries at Landbay, commented: “The buy-to-let market is set to become more complex in 2018, and as landlords move to navigate the changing environment, so too must lenders ensure that their approach to lending is robust. This is why we have chosen to refine our underlying portfolio stress tests, demonstrating our ongoing commitment to portfolio landlords.”