A landlord can have a strong personal income and still find that the rent on a particular property limits their mortgage options. Suffolk Building Society's new top-slicing criteria create another route for eligible UK and expatriate borrowers.
Announced on 27 October and effective from 28 October 2026, the change applies to Suffolk's two-year UK and expat buy-to-let products. It allows the lender to consider eligible surplus personal disposable income where the property's rent falls short of its normal affordability calculation.
What Suffolk's new criteria allow
| Criterion | Published position |
|---|---|
| Products covered by the announcement | Two-year UK and expat buy-to-let mortgages |
| Minimum rental coverage | 125% interest coverage at the product rate |
| Sole applicant | Minimum personal income of £40,000 |
| Joint applicants | Minimum combined income of £65,000, or at least one applicant earning £40,000 |
| Maximum applicants | Two |
| Holiday lets | Excluded |
Sources: Suffolk's announcement, published by Cherry on 27 October 2026, and the lender's live top-slicing criteria. Full links appear below.
Why a strong income can help when the rent falls short
Interest coverage ratio, or ICR, compares rental income with the mortgage interest used in a lender's affordability calculation. The interest rate used for that assessment matters as well as the coverage percentage.
Suffolk's announcement states an ICR of 125% for basic-rate taxpayers and 145% for higher- and additional-rate taxpayers. The new 125% test at the product rate is the minimum rental threshold for considering top-slicing. It should not be read as automatic approval at that loan size.
For example, a salaried landlord might have money left after their household spending and existing commitments, while the proposed rental property fails the lender's normal stress test. Top-slicing allows that remaining personal income to be considered. A salary figure on its own does not establish how much support is available.
What expat landlords should check
Suffolk's live criteria require personal income used for expat top-slicing to be in an accepted currency. Foreign-currency income is reduced by 20% for the affordability assessment. This adjustment means the headline sterling equivalent of overseas earnings is not necessarily the figure used when assessing the case.
Willow's view is that the practical starting point is the complete income picture: where the applicant lives, how they are paid, what evidence is available and what commitments already draw on that income. The announcement does not establish eligibility for every overseas borrower.
Which cases merit another look?
In Willow's view, this is most relevant to cases where rental affordability has been the limiting factor and the applicant may have sufficient personal income to support the shortfall. Examples worth reviewing include:
- A remortgage where the rent does not support the borrowing required under the usual stress test.
- A proposed purchase where the landlord has a strong income outside the property being financed.
- An eligible British expat financing a UK rental property while earning overseas.
For a landlord with several properties, the review should also consider existing borrowing and commitments. The new criteria do not establish that every portfolio or ownership structure will qualify.
Has rental stress testing limited your buy-to-let mortgage?
If a UK rental purchase or remortgage has been constrained by the rent, but you have income outside that property, Willow can review whether Suffolk's new approach or another lender's criteria could help.
Our buy-to-let hub explains the wider options for individual landlords and property portfolios.
Explore buy-to-let mortgage optionsFrequently asked questions
What is buy-to-let top-slicing?
Top-slicing allows a lender to consider eligible surplus personal income when rent alone does not satisfy its normal buy-to-let affordability calculation. The lender still assesses the applicant's income, spending and financial commitments.
Does meeting the income threshold guarantee a larger mortgage?
No. The minimum income requirement is an eligibility condition. The amount available depends on the lender's assessment of disposable income, rental cover, the property and the rest of the application.
Can British expat landlords use Suffolk's new criteria?
The announcement includes two-year expat buy-to-let products. Personal income must be in an accepted currency, and Suffolk applies a 20% reduction to foreign-currency income for affordability. Other expat eligibility requirements still apply.
Does the rental property still need to meet a minimum coverage test?
Yes. Rent must cover at least 125% of the mortgage interest calculated at the product rate before Suffolk will consider top-slicing. Passing this threshold does not confirm the final loan amount.
Is the new top-slicing policy available for holiday lets?
No. Suffolk's announcement covers its two-year UK and expat buy-to-let products and expressly excludes holiday let mortgages.