What is a Joint Borrower Sole Proprietor mortgage?

Full answer

JBSP mortgages are a specialist option that has become increasingly popular as house prices have made it harder for many buyers, particularly first-time buyers, to qualify for a mortgage on their income alone. **How JBSP differs from a normal joint mortgage** In a standard joint mortgage, all parties named on the mortgage are also normally registered as legal co-owners on the property title. With a JBSP mortgage, the additional applicant (often a parent) is included on the mortgage itself -- meaning their income counts towards the affordability assessment and they are equally, legally liable for repaying the mortgage -- but they are deliberately NOT registered as an owner of the property on the title deeds, so the buyer retains sole legal ownership. **Why someone would use this structure** The main benefit is boosting mortgage affordability: lenders offering JBSP products will typically assess the combined income of both the buyer and the additional borrower (sometimes with some restrictions on how much of the additional borrower's income can be used), allowing the buyer to borrow significantly more than they could based on their income alone, while the additional borrower avoids the extra Stamp Duty surcharge for additional properties (since they are not becoming a legal owner) and avoids potential Capital Gains Tax exposure on a property that is not their own home (which could otherwise arise for a parent who was a co-owner of a property that is not their main residence). **Key risks for the additional borrower** The additional borrower takes on full legal liability for the mortgage debt (the lender can pursue them for the full amount if the primary buyer fails to pay) despite having no ownership stake, no right to live in the property, and no automatic right to a share of any sale proceeds or increase in value. This liability also typically appears on the additional borrower's own credit file and counts against their own future borrowing capacity (for example, if the parent later wants their own mortgage or additional borrowing), since lenders will factor in this existing joint liability. **Coming off a JBSP mortgage later** Once the primary buyer's income has grown sufficiently (or after a set period), it is often possible to remortgage to remove the additional borrower from the mortgage, converting it to a standard sole mortgage in the buyer's name only -- but this requires the buyer to then independently qualify for the full mortgage amount on their own income and pass a fresh application/valuation, so it is not automatic or guaranteed to succeed. **Worked example** A first-time buyer earning £32,000 a year can only borrow around £140,000 on their income alone, insufficient for the £220,000 flat they want to buy. Their mother, still working and earning £45,000 a year with no significant existing debt, joins the mortgage as an additional JBSP borrower. Combining both incomes under the lender's JBSP affordability criteria allows the couple to borrow the full £200,000 needed (alongside a £20,000 deposit), with the daughter as sole legal owner on the title (avoiding the extra 5% additional-property Stamp Duty surcharge that would apply if the mother were a co-owner), while the mother remains fully, legally liable for the mortgage repayments alongside her daughter until the mortgage is either repaid or later remortgaged into the daughter's sole name. **Practical tip** Both parties should take independent legal advice before entering a JBSP arrangement, given the significant liability the additional borrower takes on without gaining any ownership interest, and should discuss and document (even if only informally within the family) a clear plan and expectation for how and when the additional borrower is intended to be removed from the mortgage.

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