6,400+ mortgages arranged

90+ lenders, £1.5bn+ lent

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

Home Movers

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)

  1. Borrower + helper(s) apply for the mortgage together.

  2. Lender assesses all incomes, commitments and credit files.

  3. Only the main buyer (the sole proprietor) goes on the property deeds.

  4. The mortgage offer names all applicants, who share the legal responsibility for the loan.

  5. Everyone must pass affordability, credit, age criteria and take independent legal advice.

  6. 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.

For many, buying a home is simply not an option due to the deposit, fees and costs involved. It can be a very expensive process and many people will struggle to purchase a property without any assistance. But did you know that if you are a council or housing association tenant in England then you may be eligible to buy your home with a discount with the ‘Right to buy’ scheme?

Right to Buy is a Government scheme that allows secure tenants to buy their home at a discounted price, depending on eligibility.

The Right to Buy is available to:

  • Secure tenants of councils
  • Non-charitable Housing Associations
  • Assured tenants of registered providers, such as Housing Associations. 

The maximum discount available is £87,200 unless your home is in London which increases the maximum discount to £116,200.

Other eligibility requirements include:

• The home you are purchasing will be your main residence

• You don’t share rooms with any other people

(Please note there are more eligibility criteria’s to meet )

How does the discount work?

If you have been a public sector tenant for at least 3 years then you could be eligible for the Right to Buy scheme. In tenancy years 3-5, the discount available will 35%. After this, the discount increases by 1% each year of tenancy until a maximum discount of 70%. The discount is slightly different if you live in a flat. In tenancy years 3-5, the discount available is 50% and for each year after that the discount increases by 2% again up to a maximum of 70%. It is important to note that as much as the maximum discount is 70k, this is capped at the maximum discount amount of £87,200 (£116,200 in London).

Do you have to repay the discount?

Only if you choose to move within 5 years! If you chose to sell your property within 5 years of purchasing then you will have to repay your discount. But if you choose to sell agent the five years, you won’t pay back anything.

Please see the table below which illustrates the amount of discount to be repaid.

Years Since PurchaseDiscount To Be Repaid
1100%
280%
360%
440%
520%

Also, it is worth noting that the percentage to be repaid will be based on the current market value rather than your original purchase price.

What is the process?

1) Check you can afford to purchase the property and pay any fees included

2) Complete a Right To Buy application form and send it to your landlord

3) Wait for your landlord to reply with an offer notice. This will tell you the property value, discount, the price, any structural problems with the property that they know about, and any terms and conditions

4) At this point you can look to apply for your mortgage, instruct a solicitor and get a property survey

5) Complete your purchase

Below is a Right to Buy calculator which can be used as a rough guide to help you work out the discount you may be eligible for under the current Right to Buy scheme. Please note that as the market value you enter will only be an estimate, the level of discount you could get may go up or down. You will only know exactly how much your home is worth once it has been valued by your landlord after you apply:

https://www.gov.uk/right-to-buy-buying-your-council-home/discounts

It’s important to remember that if you do qualify for Right to Buy, you must then carefully consider whether you can afford the costs of being a homeowner. If you do not keep up repayments on your mortgage your home could become repossessed.

We also appreciate that even those not needing to claim state or housing benefits may still be struggling to buy your first home. There are other government initiatives such as the lifetime ISA which allows you to save a tax-free lump sum that can be used to save for the deposit on your first home, and has the added boost of a government bonus of up to £1,000 a year.

How can BMI help?

If you are interested in any of the above why not book an appointment with one of our expert advisors to confirm your borrowing capacity. Call in on 01844 390910 to speak to one of the team today.