Clydesdale is cutting its maximum loan-to-income multiple to 4.49x for self-employed borrowers.
Halifax introduced similar restrictions in January.
Clydesdale’s changes apply to all cases where one or more applicants is a sole trader, part of a limited partnership or director of a limited company.
The lender says it will not affect day rate contractors that meet its policy.
In addition to self-employed income, 100 per cent of pension and allowable benefit income will be used in the loan-to-income calculation.
Applications submitted after 8pm on Wednesday March 3 will be assessed under the new criteria.
Borrowers who are already in the pipeline will not be affected.