Joint Borrower, Sole Proprietor Mortgages: Who They’re For & When They Work

November 19th 2025

If you’re struggling with affordability on your own, you might have come across something called a Joint Borrower, Sole Proprietor (JBSP) mortgage. It’s a mouthful, but the idea is simple: someone else can help you borrow more, without owning any share of the property.

In this guide, we’ll break down how JBSP mortgages work, who they’re best for, and when they can be a smart solution.

What Is a Joint Borrower, Sole Proprietor Mortgage?

A JBSP mortgage allows an extra person (usually a parent or close family member) to go on the mortgage but not on the property deeds.

This means:

They share responsibility for paying the mortgage.
They don’t own any part of the home.
They’re not caught by the extra 3% stamp duty surcharge that applies to second-home ownership.

It’s basically a way to boost affordability without adding someone as a legal owner.

Why Would Someone Use a JBSP Mortgage?

To Increase Borrowing Capacity

If your income doesn’t stretch far enough on its own, a second applicant’s income can help you borrow more. This is especially common for:

First-time buyers facing high house prices
Single applicants
People with lower or inconsistent income

To Get on the Ladder Earlier

Instead of waiting to increase income, build savings or pay off debts, a JBSP mortgage can speed up the process.

To Avoid Family Members Owning Part of the Home

Parents often want to help, but don’t want to be tied to the property legally. JBSP works perfectly here.

To Avoid Stamp Duty Surcharge

If a parent went on the deeds, they may pay the additional 3% stamp duty. JBSP avoids this because the helper isn’t a legal owner.

Who Are JBSP Mortgages Ideal For?

JBSP is most commonly used by:

First-time buyers

Especially young professionals whose incomes haven’t caught up with house prices in their area.

Parents helping adult children

This is by far the biggest category. Parents can use their income to support the mortgage while the child owns the home.

Couples where one partner has lower income or credit issues

If one person can’t go on the mortgage (credit, affordability, past financial issues), they can still live in the property while the other partner and a helper apply.

Single parents

Where one income alone isn’t enough to meet lender affordability models.

Older borrowers

Sometimes adult children go on the mortgage to help parents downsize or move, though lenders vary on age limits.

How a JBSP Mortgage Works (Step-by-Step)

Borrower + helper(s) apply for the mortgage together.
Lender assesses all incomes, commitments and credit files.
Only the main buyer (the sole proprietor) goes on the property deeds.
The mortgage offer names all applicants, who share the legal responsibility for the loan.
Everyone must pass affordability, credit, age criteria and take independent legal advice.
Over time, the helper can often be removed from the mortgage when affordability improves.

Pros of a JBSP Mortgage

Boosts affordability significantly

Can help you borrow more than you could alone.

No extra stamp duty for the helper

Parents, siblings or partners help without owning part of the home

Flexible exit — they can come off later

Good for long-term affordability growth

Perfect for careers with strong income progression.

Cons to Consider

All borrowers are legally responsible for the full mortgage

If payments are missed, everyone’s credit file is affected.

Age limits can restrict mortgage terms

If the helper is older, their age may reduce the maximum mortgage term.

The helper’s borrowing may be affected

Their income is tied to this mortgage, which can limit their future applications.

Some lenders require legal advice

Independent legal advice is often mandatory for the non-owner borrower.

When Does a JBSP Mortgage Work Best?

When the main buyer’s income is rising

For example, early-career roles with strong salary progression.

When the helper has stable, strong income

Often a parent or relative with good credit and minimal debts.

When other options don’t fit

Such as when:

A guarantor mortgage isn’t available
A gifted deposit still isn’t enough
A partner can’t go on the mortgage

When avoiding stamp duty surcharge matters

A JBSP mortgage can work really well when one partner already owns a property and the couple want to buy a home together, but don’t want the existing property to trigger the additional 3% stamp duty surcharge.
Instead of adding the partner who already owns a property to the deeds, they can simply go on the mortgage to support affordability — avoiding the second-home tax charge.

**When JBSP Might Not Be Suitable**

If the helper wants to own part of the home → Joint mortgage may be better.
If the helper is near retirement → affordability may be restricted.
If the buyer’s income won’t realistically improve → removal later may be hard.
If multiple applicants already have commitments → affordability may still fall short.

Can the Helper Be Removed Later?

Yes — this is one of the best parts of JBSP mortgages.

Once the main borrower’s income improves, or once debts are reduced, you can request a remortgage or product transfer to remove the helper.

Is a JBSP Mortgage Right for You?

Every situation is different. A JBSP mortgage can be incredibly helpful for buyers who need extra support to get onto the property ladder, but it isn’t right for everyone.

Speaking with a broker gives you personalised guidance, checks lender criteria, and helps you choose the right solution for your circumstances.

Need Advice?

If you’d like to explore whether a JBSP mortgage could work for you, we’re happy to help.

Get in touch and we can run through your options, affordability and the lenders offering JBSP products right now.

In the perennial debate of renting versus buying a home, opinions often sway towards the merits of renting for its flexibility and perceived lack of responsibility. However, while renting offers immediate flexibility, buying a house is a long-term investment that brings numerous advantages, both financial and emotional, making it a prudent choice for many. Let’s delve into why buying a house is often a better option than renting.

1. Equity Building

When you rent a property, you’re essentially paying someone else’s mortgage, providing them with equity. In contrast, every payment you make as a homeowner contributes to your equity in the property. Over time, this builds up your net worth and serves as a form of forced savings, offering a path to financial stability and future wealth.

2. Stability and Predictability

Rent prices can fluctuate unpredictably due to various factors such as market conditions, landlord decisions, or changes in the neighbourhood. Buying a house, on the other hand, provides stability as your housing costs remain relatively constant, allowing you to budget more effectively over the long term. Moreover, homeownership offers protection against inflation; as the cost of living rises, your housing expenses stay relatively stable.

3. Freedom for Personalisation

Owning a home grants you the freedom to personalise and modify your living space according to your preferences. Whether it’s painting the walls, renovating the kitchen, or landscaping the backyard, homeowners have the autonomy to make changes that reflect their lifestyle and tastes. This level of personalisation is often restricted in rental properties, where landlords may impose limitations on alterations or renovations.

4. Long-Term Investment

Real estate has historically proven to be a lucrative long-term investment. While short-term market fluctuations may occur, the overall trend tends to appreciate over time. Buying a house allows you to capitalise on this appreciation, potentially yielding significant returns when you decide to sell. Moreover, owning property serves as a hedge against inflation, preserving your purchasing power and providing a tangible asset that can appreciate in value over the years.

5. Sense of Community and Belonging

Owning a home fosters a sense of community and belonging. When you put down roots in a neighbourhood, you’re more likely to establish connections with your neighbours, participate in local events, and engage in community initiatives. This sense of belonging contributes to your overall well-being and enhances your quality of life, fostering a deeper connection to your surroundings and creating a place to call home.

6. Rental-Free Retirement

Paying off your mortgage means you’ll enter retirement without the burden of monthly housing expenses, providing financial security during your golden years. With renting, you’re subject to the whims of the rental market, potentially facing rent increases that can strain your retirement budget. By owning your home outright, you can enjoy a comfortable retirement without the worry of rising housing costs.

7. Legacy and Generational Wealth

Homeownership enables you to build a legacy and create generational wealth for your family. Passing down a home to your children or grandchildren can provide them with a solid financial foundation and serve as a tangible symbol of your hard work and achievements. Real estate has the potential to appreciate significantly over multiple generations, offering a lasting legacy that transcends monetary value.

In conclusion, while renting offers short-term flexibility, buying a house provides a myriad of long-term benefits that extend far beyond mere shelter. From equity building and financial stability to personalisation and community ties, homeownership offers a pathway to wealth accumulation, security, and a place to call your own. By weighing the advantages of buying against the limitations of renting, individuals can make informed decisions that align with their long-term financial goals and aspirations.