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.

The housing market has been so unstable this last year, it is hard to predict what will happen in 2024 – whether house values will continue to fall and mortgage rates rise or if there will be a plateau as loans stabilise?

Here we look at what 2023 was like for the property market, and if experts believe trends will continue or change next year.

Property market in 2023

The year began with mortgage advisors only being able to offer sky-high rates following the government’s Mini Budget in September 2022, which caused the pound to drop and interest rates to surge.

As a result of fewer people being able to afford mortgage rates, there was less demand to buy properties, which has resulted in falling prices.

Indeed, according to the Halifax House Price Index, values dropped by 3.2 per cent from October 2022 to October 2023, which is the equivalent of around £10,000 on the average property in the UK.

When it comes to the buy-to-let market, however, landlords have fared well, as first-time-buyers have not been able to get on the property ladder. Therefore, the demand for rental properties has grown, which has meant rents have increased.

This has been good for those who own their assets outright, but those with mortgages on their properties have still been subject to high mortgage rates. This meant their profit could have been wiped out, despite the higher rents.

With all this in mind, what are the predictions for the property market for 2024?

Rightmove predictions

The property search website Rightmove has predicted asking prices will be a further one per cent lower than they currently are, due to the rising competition between sellers.

Tim Bannister from Rightmove stated: “The underlying level of good demand at the right price makes it unlikely that we will see a more significant drop in prices next year.”

This year has shown that buyers are still keen to get on the market, in spite of mortgage costs, which has helped to stop prices from plummeting.

However, vendors can expect to wait an average of 66 days to find a buyer, which has increased from 45 days last year.

To make a property more appealing to buyers, Mr Bannister advised making the asking price more competitive instead of having to reduce it later on down the line.

“Pricing right at the outset maximises the initial impact among local buyers and gives new sellers a much greater likelihood of a successful sale,” he added.

With regards to mortgage rates, Rightmove estimated affordability will still remain challenging next year. It believes interest rates will continue to be elevated, which will mean homebuyers will not be able to afford as much property as they had wanted.

This, in turn, could force house prices to come down, putting buyers in a better position to negotiate on price.

Zoopla predictions

Property website Zoopla also predicted house prices will continue to fall next year, estimating they will decline by two per cent in 2024.

It stated that sellers will continue to adjust their asking prices according to demand, which will be dependent on mortgage rates and affordability. As long as rates remain high and the cost-of-living crisis continues, buyers will want more for their money when purchasing a home.

Thanks to the Bank of England projecting that inflation will fall to around two per cent in 2025, this could improve household finances, which will boost buyer demand beyond next year.

Executive director of research at Zoopla Richard Donnell noted that mortgage rates of between four and five per cent are still low, even though they are much higher than Brits are used to.

He said that if they remain at this level, it is likely house price growth will remain “in the low single digits for the next one to two years, below the projections for growth in household incomes”.

There could also be fewer buyers next year, thanks to political unrest due to an expected General Election. Buyers are also more reluctant to move at the moment, as they are worried house prices will continue to fall and they will be left in negative equity.

Lloyds Banking Group predictions

Lloyds Banking Group is more pessimistic about the state of the property market, estimating that house prices will have fallen by as much as 4.7 per cent this year and 2.4 per cent in 2024, Money Week reported.

It stated that values are unlikely to pick up again until the following year, which could put vendors off selling their properties until 2025 to avoid losing money on their assets. Having fewer homes on the market could also help to drive up prices, as there is more competition among buyers.