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.

Many employees take comfort in knowing their employer offers Death in Service (DIS) benefit — a lump-sum payment to their loved ones if they pass away while employed. It’s a great perk, but it’s important to understand that relying on it as your only protection comes with some serious drawbacks.

Let’s look at why.

What Is Death in Service?

Death in Service is a benefit provided by many employers. If you die while employed, your family receives a lump sum — usually a multiple of your salary (often 3x or 4x your annual earnings).

It’s a valuable part of your employee package, but it’s not the same as a personal life insurance policy.

It’s Not Guaranteed Forever

Your Death in Service benefit only lasts as long as you’re employed by that company.
If you change jobs, are made redundant, or move to an employer that doesn’t offer the same benefit, you lose your cover immediately.

And unfortunately, life events — like a new mortgage or starting a family — often happen around the same time as career changes. The last thing you want is a protection gap when your responsibilities are growing.

Your Employer Could Remove or Change It

Death in Service is an employee benefit, not a personal policy you own.
That means the company can change or withdraw it at any time — especially during restructures or cost-saving measures.

With personal life cover, you stay in control. You choose the amount, the term, and you keep it regardless of where you work.

Some Policies Have Restrictive Conditions

Not all DIS schemes are as straightforward as they sound. Some older or more limited policies have conditions such as:

The death must occur on company premises
The death must occur during working hours
The employee must be actively employed at the time of death
While these aren’t typical of modern schemes, it’s a reminder that you may not be covered in all circumstances.

It Might Not Be Enough

Even if your employer offers 4x your salary, that may not stretch very far.
For example, someone earning £40,000 would leave £160,000 — which might not be enough to clear a mortgage, support dependants, or provide lasting financial stability.

A personal life policy can be tailored to your family’s real needs, ensuring your loved ones are fully protected.

The Smarter Approach

Think of Death in Service as a bonus, not a plan.
It’s a nice safety net to have — but it shouldn’t replace personal life insurance that you own and control. A private policy moves with you, pays out on your terms, and ensures your family’s future doesn’t depend on your job.

Final Thoughts

Your employer’s Death in Service cover is a welcome benefit, but it’s not a substitute for proper protection.
If you’re unsure what cover you currently have — or how much your family would actually receive — it’s worth reviewing it alongside your personal life insurance options.

We can help you work out what’s already in place and where the gaps might be — so you can make sure your loved ones are fully protected, no matter what happens.