Joint Borrower Sole Proprietor Mortgages

Family support when you need it

Our Joint Borrower Sole Proprietor (JBSP) residential mortgage range* means the income of up to 4 family members can be used for affordability so that your client can borrow more without their family members co-owning the property.

The family members sponsor a relative by including their incomes in our affordability assessment without needing to be on the title deeds and jointly owning the property.

As it gets harder for them to get on the housing ladder, first time buyers are taking a particular interest.

Although sponsors can stay on for the full term on our JBSP range, for most it’s a temporary boost, so that when they can afford the mortgage on their own, they can remove the family members who have helped apply for the mortgage.

Who can sponsor your client?

Sponsors can only be your client’s:

  • spouse
  • mother or father
  • brother or sister
  • child
  • grandparent or grandchild
  • legal guardian

Important: Your sponsors can't live in the property.

To make a JBSP mortgage application, you must complete

If a family member is providing the purchase deposit, you may also need to complete a Waiver Form.

Case Study

Find out how, with support from her family, we helped Rhian take a step on the property ladder.

GIF showing how we helped Rhian onto the property ladder

Frequently asked questions

Whose household expenditure will need to be inputted for affordability?

Household expenditure for both the borrower and the sponsor will need to be inputted for the affordability calculation.

Do I need to input sponsors' mortgage debt in affordability?

You don’t need to input the sponsors’ mortgage debt in the initial affordability calculation but, in order to take account of it, the remaining mortgage debt of joint borrowers must be subtracted from the results.


Sponsors’ outstanding mortgage is £152,000,mortgage applied for is £150000. Affordability will need to cover £152k and 150k = £302k plus.

The sponsors’ mortgage balance does not need to be added to expenditure.

What type of JBSP mortgages are available?

These mortgages are only available for purchases and capital repayment.

When will Independent legal advice be needed?

Any non-owning borrower will need to get independent legal advice.

Each non-owning party will need to provide a completed Certificate of Independent Legal Advice before the mortgage is completed and the funds are released.

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