What are Joint Borrower Sole Proprietor Mortgages?

If you’re struggling to get onto the property ladder, a joint borrower sole proprietor (JBSP) mortgage could be a good option.

Understanding JBSP mortgages

A joint borrower sole proprietor mortgage lets you team up with up to three other people, usually parents or family members, to increase how much you can borrow. The deeds are in your name, but everyone on the mortgage shares the responsibility for making payments.

How joint borrower sole proprietor mortgages work

When you apply for a JBSP mortgage, lenders look at what everyone earns and spends. Say you earn £30,000 a year. On your own, you'd typically borrow between £120,000 and £135,000 (lenders usually let you borrow 4 to 4.5 times your salary). But add a parent earning £40,000, and suddenly you could borrow £280,000 to £315,000, depending on which lender you choose.

Everyone on the mortgage is equally responsible for the payments. If you miss a payment, your family members have to cover it. Any late or missed payments damage everyone's credit score. That's why you should only do this with people you completely trust and whose finances you understand - their debts and credit history will affect how much you can borrow, and they need to be financially stable enough to help if you ever struggle with payments.

The key benefits

The Stamp Duty advantages alone make JBSP mortgages attractive. First-time buyers in England and Northern Ireland pay no Stamp Duty on properties up to £300,000, with relief available on properties up to £500,000. If your parents bought the house with you as joint owners (a standard joint mortgage), you'd lose this tax break because they already own a property. But with a JBSP mortgage, your parents aren't owners—they just help you borrow more. This means you keep your first-time buyer status and the valuable tax savings that come with it.

You'll also have more freedom in choosing your home. Unlike some schemes that only work for new-build properties, JBSP mortgages let you buy any type of home. And once you're earning more or have paid off enough of the mortgage, you can remove your family members and take it on yourself.

Important considerations

Keep in mind that even though your family is helping you financially, they won't own any part of the property or benefit from it in any way, even if it increases in value. Also, being on your mortgage could make it harder for them to borrow money in the future as lenders will see they're already committed to your mortgage.

Your relationship with everyone involved needs to be strong and stable. If things go wrong between you, getting them off the mortgage isn't straightforward. You'll need your lender's permission, and you'll have to prove you can afford all the payments on your own.

Talk to one of our qualified mortgage advisers to assess whether a JBSP mortgage is a good fit for you.