With Bank Rate now at 4%, many first-time buyers are finding affordability tests harder to pass on one income. One option families are asking about is a joint borrower sole proprietor (JBSP) mortgage, and at least one building society has just made its rules more flexible.
What is a JBSP mortgage?
A JBSP mortgage lets a parent, grandparent or other relative go on the mortgage to boost affordability, without going on the property title. Your child owns the home; you share responsibility for the monthly payments.
Because the supporting relative does not own a share of the home, the purchase may not trigger the higher stamp duty rates for additional properties. That depends on everyone's circumstances, so always check with your conveyancer or tax adviser.
What has changed?
On 6 November 2026, Vernon Building Society announced wider JBSP criteria, including:
- mortgage terms that can run beyond the supporting borrowers' intended retirement age
- up to four applicants and their incomes considered together
- removal of its rule that the owner must afford at least half the monthly payment alone
- split repayment terms, so parts of the loan can run over different periods
This matters for parents in their 50s and 60s. In the past, a shorter term to fit a parent's retirement age often pushed the monthly payment up so much that the case didn't work.
What lenders will look at
Criteria vary widely between lenders. Most will want to see:
- affordability for all applicants, including the parents' own mortgage and outgoings
- a clear plan for income in retirement if the term runs past it
- independent legal advice for the supporting borrowers in many cases
- how and when the owner could take the loan over in their sole name
Remember that every borrower is jointly responsible for the whole debt. If payments are missed, it can affect everyone's credit file.
Quick tips
- Talk as a family first. Agree who pays what, and what happens if circumstances change.
- Check your own borrowing. Your existing mortgage and retirement plans will be part of the assessment.
- Compare the alternatives. A gifted deposit, or a guarantor-style product, may suit some families better.
- Think about protection. Life and income cover can protect everyone named on the mortgage.
- Plan the exit. Ask how your child could remortgage into their sole name later.
How OMB can help
Our CeMAP-qualified advisers search the whole of the market for residential mortgages and can show you which lenders consider JBSP and how each one treats retirement age. See how we helped a family in our Birmingham gifted-deposit case study, run the numbers with our borrowing calculator, or download our free later life mortgages guide.
Sources
- Mortgage Solutions, 6 November 2026: Vernon BS eases JBSP criteria
- Trading Economics, 5 November 2026: Bank of England raises Bank Rate to 4%
- GOV.UK: Higher rates of Stamp Duty Land Tax
To talk it through, contact us or start your enquiry.
Important: This guide is general information, not personal advice. Rules, rates and lender criteria change; speak to an adviser about your circumstances. Your home may be repossessed if you do not keep up repayments on your mortgage.