Joint Borrower Sole Proprietor Mortgages (JBSP Mortgages) Explained

Friday 27 February, 2026

What You Need to Know About JBSP Mortgages

A Lonsdale mortgage adviser can provide the information on how a Joint Borrower Sole Proprietor (JBSP) mortgage can help individuals buy a property when their income alone does not meet a lender’s affordability criteria.

This type of mortgage allows more than one person to share responsibility for the repayments, while legal ownership of the property remains with a single borrower.

Understanding how a JBSP mortgage works, who it may suit, and the risks involved is essential before deciding whether this route is appropriate for your circumstances.

What is a Joint Borrower Sole Proprietor mortgage?

A JBSP mortgage is an arrangement where multiple people are named on the mortgage and are jointly responsible for the repayments, but only one person is listed as the legal owner at the Land Registry.

Lenders may consider the incomes of all borrowers when assessing affordability, even though only the sole proprietor is registered as the owner. This structure can help increase the amount that can be borrowed without adding additional names to the property deeds.

How does a JBSP mortgage work?

All borrowers named on the mortgage share joint and several liability, meaning each person is legally responsible for ensuring the full monthly payment is made. If a payment is missed, the lender can pursue any borrower for the outstanding amount.

Despite this shared financial responsibility, only the sole proprietor has legal ownership of the property. They hold the right to live in the property and benefit from any increase in its value. Supporting borrowers do not gain ownership rights unless separate legal agreements are put in place.

Who might benefit from a JBSP mortgage?

A JBSP mortgage may be suitable for:

First‑time buyers who need support from parents or close family members
Buyers whose income alone does not meet affordability requirements
Individuals who want to retain sole legal ownership for future planning or inheritance reasons

This structure can help buyers access a higher borrowing amount while keeping ownership simple. However, it is important that all parties understand the financial and legal implications before proceeding.

Who can help with a Joint Borrower Sole Proprietor mortgage?

Not all lenders offer JBSP mortgages, and eligibility criteria vary. A regulated mortgage adviser, such as those at Lonsdale, can help identify which lenders currently provide these products and assess whether a JBSP arrangement is appropriate for your circumstances. Professional advice ensures that both the purchaser and supporting borrowers understand the commitments involved and how the mortgage may affect future financial plans.

Benefits of a Joint Borrower Sole Proprietor mortgage

A JBSP mortgage can offer several advantages:

Increased borrowing potential: Lenders may consider multiple incomes when assessing affordability.
Sole legal ownership: Supporting borrowers are not added to the property deeds, which may simplify future planning or avoid complications around ownership.
Flexibility: The structure can support buyers who expect their income to increase over time.

It is important to note that tax treatment depends on individual circumstances and may change. Anyone concerned about potential tax implications should seek independent tax advice.

Potential drawbacks of a JBSP mortgage

A JBSP mortgage also carries risks that all borrowers should consider:

Joint liability: Every borrower is responsible for the full mortgage repayment. Missed payments can affect the credit files of all parties.
Impact on supporting borrowers’ future borrowing: Being named on a JBSP mortgage may reduce the ability of supporting borrowers to take out credit or a mortgage in their own name.
Relationship considerations: As JBSP arrangements often involve family members, it is important to consider how financial commitments may affect personal relationships if circumstances change.
Age and affordability constraints: Some lenders apply maximum age limits or require evidence of retirement income for older supporting borrowers.

Legal ownership with a Joint Borrower Sole Proprietor mortgage

With a JBSP mortgage, the sole proprietor is the only legal owner of the property. Supporting borrowers do not automatically gain any legal or beneficial interest in the property. If the parties intend to create any form of shared interest or financial protection, this must be documented separately through independent legal advice.

Can a JBSP mortgage change in the future?

Many JBSP arrangements are designed to be temporary. As the sole proprietor’s income increases or circumstances change, it may be possible to remortgage into a standard sole‑borrower mortgage and remove the supporting borrowers from the liability. Whether this is possible will depend on lender criteria at the time, the borrower’s financial position, and market conditions.

Importance of professional advice for a JBSP mortgage

A JBSP mortgage involves financial, legal and potentially tax considerations for everyone involved. Taking advice from a regulated mortgage adviser helps ensure that the arrangement is suitable, sustainable, and aligned with each party’s longer‑term plans. Independent legal advice is also strongly recommended so that all parties understand their rights and responsibilities.

Amy Kadir, Lonsdale Mortgage Broker in St Albans said:

“A JBSP mortgage can provide a valuable route onto the property ladder, but it’s important that all parties fully understand their commitments. At Lonsdale, our mortgage advisers work closely with clients to assess whether this type of arrangement appears appropriate and sustainable for their goals.”

Take the next step with Lonsdale

If you are considering a Joint Borrower Sole Proprietor mortgage or want to explore whether a JBSP structure could support your property plans, speak to one of our mortgage advisers at Lonsdale. Tailored, regulated advice can help you make informed decisions and move forward with confidence.

Please note: As a mortgage is secured against your home, it may be repossessed if you do not keep up the mortgage repayments. This article is for information only and does not constitute advice.

Sources: HM Land Registry - GOV.UK, First Time Buyer & Family Assisted Mortgages | Family Building Society, Income Booster | Joint Borrower Sole Proprietor mortgages, What is a Joint-Borrower-Sole-Proprietor Mortgage?, What Is a JBSP Mortgage? How Joint Borrower Sole Proprietor Mortgages Work | Mortgage Bridge, Compare Best Joint Borrower Sole Proprietor Mortgages (JBSP) | money.co.uk