For most first-time buyers, the deposit is the wall they can't get over. Affordability is often fine — plenty of people pay more in rent than they would on a mortgage — but saving £15,000–£30,000 while renting is another matter entirely.
That's why one recent criteria change caught our attention: at least one high-street lender will now lend beyond 95% loan to value — up to 100% — on a Joint Borrower Sole Proprietor basis. In plain English: with the right family support on the mortgage, a buyer can purchase a home with no deposit at all, and the family members supporting them never go on the deeds.
What is a Joint Borrower Sole Proprietor mortgage?
A Joint Borrower Sole Proprietor (JBSP) mortgage separates two things that normally go together: who is on the mortgage, and who owns the property.
Up to four people can be named on the mortgage — typically a buyer plus one or both parents — and all of their incomes can be used to support the borrowing. But only the buyer (the "sole proprietor") goes on the title deeds. The joint borrowers are helping with the repayments and standing behind the loan, without owning any share of the home.
That last point matters for two reasons:
- Stamp duty. Because the joint borrowers don't acquire an interest in the property, the higher rates of stamp duty for additional properties generally don't apply to them — a common problem when parents buy jointly the traditional way. And if the buyer is a first-time buyer, first-time buyer stamp duty relief is normally preserved.
- Capital gains tax. With no ownership share, there's usually no CGT exposure for the parents when the property is eventually sold.
We're mortgage advisers rather than tax advisers, so where tax is a deciding factor we'd always suggest specialist advice — but structurally, JBSP is far cleaner than putting mum and dad on the deeds.
The change: JBSP above 95% — up to a 100% mortgage
JBSP itself isn't new — it's been a mainstay for buyers whose income doesn't quite stretch. What's changed is the loan to value. JBSP lending has generally been capped at 95%, meaning the buyer still needed a 5% deposit. Now, going beyond 95% — right up to lending the full purchase price — is possible, with loans available up to £675,000 at 100% LTV.
Understandably, the conditions above 95% are tighter than standard JBSP:
- Immediate family only — joint borrowers must be a spouse, parent, grandparent, child, grandchild, brother or sister of the buyer (step, half, adopted and in-law relations all count).
- Homeowners themselves — the joint borrowers must own their own residential property.
- Minimum £75,000 combined income — the joint borrowers must collectively earn at least £75,000 and show disposable income that could genuinely support the mortgage.
- Capital repayment only, over a maximum term of 35 years.
- Purchases and pound-for-pound remortgages — no capital raising.
- Independent legal advice is required for every joint borrower, so they fully understand what they're signing up to.
- Maximum of two households on the application, with the outgoings of both assessed in the affordability calculation.
Below 95%, standard JBSP criteria are more flexible — joint borrowers don't need to meet the income floor, and in some cases don't even need to be family. So if a buyer has even a small deposit, more doors open. But for those with none, 100% is now a route.
A worked example: buying with no deposit
Sarah is 29, works in London and rents in Brentwood for £1,300 a month. She earns £38,000. Between rent, travel and living costs, she's managed to save very little — and watching prices rise faster than her savings is demoralising.
Her parents own their home outright in Shenfield and have a combined income of £80,000. They'd like to help but don't want to hand over a lump sum or take ownership of a second property, with the stamp duty surcharge that brings.
Sarah finds a flat for £270,000. On a JBSP basis with her parents as joint borrowers, the lender considers the household's combined income of £118,000 — comfortably supporting a £270,000 loan at 100% of the purchase price. No deposit. Capital repayment over 35 years; at an illustrative rate of 5.75%, that's roughly £1,494 a month — not far from the rent she's paying now, except the balance is falling every month.
Her parents never appear on the deeds: no additional-property stamp duty, no CGT exposure, and Sarah keeps her first-time buyer status. In a few years, once her salary has grown and she has built equity, she can remortgage into her sole name and release her parents entirely.
Rates, criteria and figures are illustrative and for information only — the right structure depends entirely on your circumstances, and lending is always subject to affordability and credit checks.
Standard JBSP vs the 100% route at a glance
| Standard JBSP (up to 95%) | Above 95% — up to 100% | |
|---|---|---|
| Deposit needed | 5% or more | Potentially none |
| Who can join the mortgage | Up to 4 applicants; more flexibility on who they are | Immediate family only, who are homeowners themselves |
| Joint borrower income | No set minimum | £75,000+ combined, with clear disposable income |
| Repayment type | More options | Capital repayment only, max 35 years |
| Purpose | Purchase and remortgage | Purchase and pound-for-pound remortgage only |
| Maximum loan at top LTV | Varies by lender | £675,000 at 100% LTV |
What to weigh up before going ahead
A 100% mortgage is a serious commitment, and JBSP asks a lot of the joint borrowers. Three things we'd want any family to be clear-eyed about:
- Everyone on the mortgage is fully liable. Joint borrowers aren't guarantors of last resort — they're borrowers. If payments are missed, it affects their credit files and, ultimately, their own home could be at risk through enforcement of the debt. This is exactly why independent legal advice is required.
- It affects the parents' own borrowing. The JBSP commitment will be factored into any future mortgage or lending application the joint borrowers make.
- Negative equity risk is real at 100%. With no deposit buffer, even a modest dip in property values means owing more than the home is worth for a period. That mostly matters if you need to sell early — but it should be part of the conversation.
JBSP works best as a stepping stone, not a life sentence. The plan from day one should include the exit: remortgaging into the buyer's sole name once income and equity allow, releasing the family from the commitment.
Is this right for your family?
The 100% JBSP route suits a specific situation: a buyer with solid income prospects but no deposit, and close family who earn well, own their own home, and want to help without gifting cash or taking on ownership. If that sounds familiar, it's well worth exploring — alongside the alternatives, from small-deposit schemes to gifted deposits, which may suit other circumstances better.
As independent brokers we can compare the whole market — including the lenders offering JBSP at every loan to value — and tell you honestly which structure fits.
Wondering whether a Joint Borrower Sole Proprietor mortgage could get you (or your children) onto the ladder? Call us on 01277 564 054 or send a message — no jargon, no pressure.
Talk to an AdviserFAQs
A Joint Borrower Sole Proprietor (JBSP) mortgage lets up to four people be named on the mortgage while only one (or a couple) is named on the property deeds. Typically parents join their child's mortgage so their income boosts affordability — but they have no ownership stake, which usually avoids the second-property stamp duty surcharge and capital gains tax exposure.
Yes — in specific circumstances. At least one high-street lender will now lend beyond 95% and up to 100% loan to value on a Joint Borrower Sole Proprietor basis, for loans up to £675,000. The joint borrowers must be immediate family members who are homeowners themselves with a combined income of at least £75,000, and the mortgage must be capital repayment over a maximum of 35 years.
Generally no. Because joint borrowers are on the mortgage but not on the title deeds, they don't acquire an interest in the property, so the higher rates of stamp duty for additional properties usually don't apply. Tax treatment depends on individual circumstances, so specialist tax advice should be taken where needed.
Above 95% loan to value, joint borrowers must be immediate family of the proprietor — spouse, parents, grandparents, children, grandchildren, brothers or sisters, including step, half, adopted and in-law relations. They must be residential homeowners themselves and collectively earn at least £75,000 with demonstrable disposable income. All joint borrowers must take independent legal advice.
Yes. The usual route is to remortgage in the proprietor's sole name once their income has grown or the loan-to-value has fallen enough for the mortgage to be affordable on their own. Many families treat JBSP as a stepping stone for the first few years rather than a permanent arrangement.