West Brom Building Society has reduced its affordability stress rate by as much as 1.15%.
The changes mean an average customer could get up to £28,000 more towards the cost of their home, representing a 13% increase for loans above 85% Loan-to-Value (LTV).
The association says the move is aimed at supporting all types of borrowers, especially first-time buyers.
For example, a first-time buyer earning £50,000 with a 10% deposit could see their loan increase by around £21,500, while a home mover earning £75,000 with a 10% deposit could get up to an extra £40,000 for their next home.
West Brom Building Society head of intermediaries Alasdair McDonalds says: “Helping people into home ownership is at the heart of what we do in the mutuals sector. By innovating our affordability approach, we are helping more customers access the loans they need in a responsible and sustainable way.”