Guide · 10 min read
Why every SPV mortgage carries a personal guarantee, who signs, what it covers, the independent legal advice requirement, and what happens if the company defaults.
Written by Matt Lenzie · Published 10 June 2026
Advice from
Matt Lenzie · 25+ year career banker (Bank of Scotland, Lloyds Banking Group). £300m+ raised for property clients.
25+ year career banker (Bank of Scotland, Lloyds Banking Group). £300m+ raised for property clients.
A personal guarantee is a director's legally binding promise to repay the company's mortgage personally if the company cannot. On limited company buy-to-let it is not a negotiating point or a sign of a weak application: it is a standard condition of effectively every lender on the market, and it is the reason the limited company wrapper does not put the mortgage itself at arm's length from you.
Because the guarantee is the moment where company borrowing touches your personal balance sheet, it deserves to be understood before offer stage, not skim-read at the solicitor's desk. This guide covers why lenders require a personal guarantee, who signs, what the document actually says, the independent legal advice ritual, what enforcement looks like, and the terms that can sometimes be negotiated.
Because limited liability, the feature that makes a company attractive to you, is precisely the feature that worries a lender. An SPV is a box with a property in it: if the loan sours and the property sells for less than the debt, a company with no other assets simply dissolves, and without a guarantee the lender absorbs the shortfall while the directors walk away and incorporate again next week. No prudent lender prices that asymmetry into a mainstream mortgage rate, so the market closed it with a standard document instead.
The personal guarantee closes that asymmetry. It puts the people who control the company behind the company's promise, aligning your downside with the lender's, and it is one reason company buy-to-let is priced only modestly above personal buy-to-let rather than dramatically so: the lender's recourse ends up broadly similar in both structures. Underwriting standards in this market run on prudent lines consistent with the PRA's SS13/16 expectations, and director recourse is part of that settled architecture. Treat the guarantee as the entry ticket to SPV mortgage pricing, because that is what it is.
The working rule across the panel: all directors, plus any shareholder above a threshold that most lenders set around 20 to 25%. A spouse holding 50% of the shares but no directorship should still expect to sign. Corporate shareholders complicate the picture, lenders will look through holding structures to the humans in control, and layered company structures narrow the lender pool for exactly this reason.
The threshold logic is worth understanding rather than memorising, because it varies by lender: the lender wants guarantees from everyone with meaningful control of, or meaningful economic interest in, the borrower. A 10% shareholder may escape at one lender and be required at another; a person with significant control on the Companies House register will rarely escape anywhere. We check the shareholding against the chosen lender's threshold before application, since a surprise guarantor discovered at offer stage is a delay at best and a withdrawal at worst.
Practical consequence for structuring: shares and liability travel together. Gifting 30% of the SPV to a family member for dividend planning also volunteers them for a personal guarantee on every future loan, a point worth weighing with your accountant before the shareholding is set. We flag it during the structure check on every new company case.
Guarantee documents are shorter than mortgage offers and heavier per page. Read yours for four terms:
None of this is exotic, but all of it is real, and the time to understand it is before the valuation fee is spent.
Most lenders require each guarantor to obtain independent legal advice (ILA) before signing: a solicitor unconnected to the transaction explains the guarantee's effect, witnesses the signature, and certifies the advice was given. From the lender's side this is enforceability armour, since a guarantor who certified that they understood the document cannot later claim they did not. From your side, treat it as a genuinely useful checkpoint rather than a rubber stamp: it is the one moment a professional whose only client is you reads the document's scope, cap and duration aloud.
Logistically it is a short fixed-fee appointment, increasingly done by video, and it sits on the critical path to completion: late ILA is one of the routine causes of drawdown delay, so we diarise it the day the offer is issued, not the week funds are due. Three practical notes: each guarantor needs their own adviser (the transaction solicitor cannot double up, that is the "independent" doing its work); spouses guaranteeing the same loan generally need separate advice for the same reason; and the certificate has a shelf life with some lenders, so an ILA done months before a delayed completion may need refreshing. None of this is difficult, all of it is calendar management.
In sequence, because the order matters to how worried you should be. The lender's first recourse is the security: the property is repossessed and sold, and on a loan written at 75% loan-to-value the sale usually clears the debt, which is why most guarantee stories end before they begin. The guarantee is called for the gap when it does not: a market fall, accrued arrears and costs, a distressed sale price.
A called guarantee is a personal debt claim against you for the shortfall. The lender can negotiate terms, take judgment, enforce against personal assets, and in extremis pursue bankruptcy, and the default plus any judgment will scar your personal credit record at exactly the moment you may be trying to refinance other properties. The mitigation is not in the document; it is in the lending: sensible leverage, honest rent assumptions, and a stress test passed with headroom rather than at the margin. Run your own numbers through our buy-to-let stress test calculator and you are looking at the same arithmetic an underwriter will.
At the edges, sometimes. Capped guarantees, percentage guarantees and time-limited terms exist across the panel, and on lower-LTV or stronger cases there is occasionally room to choose a lender whose standard guarantee terms are simply lighter; that choice is part of what whole-of-market broking is for. Personal guarantee insurance also exists, a policy that covers a portion of a called guarantee in exchange for an annual premium, more common in trading-company lending but available to landlords who want the edge insured.
What you will not find in non-regulated company buy-to-let is a mainstream lender that waives the guarantee altogether: an unguaranteed SPV loan exists only at pricing and leverage that defeat the purpose. If a structure is pitched to you that promises company borrowing with no personal recourse at normal pricing, scrutinise it the way you would any other too-good story in this market.
While everything performs, barely. A guarantee is contingent liability: it does not appear on your credit file, and it does not directly reduce a personal affordability calculation the way a loan repayment would. Two honest caveats. Lenders ask: mortgage and finance applications routinely require you to declare guarantees given, and portfolio lenders aggregate your guaranteed exposure when assessing the next company loan, so a stack of guarantees is visible to the market even though it is invisible to the credit bureaux. And if a guarantee is ever called, the contingency becomes a hard debt with full credit consequences.
For most directors the working summary is this: the guarantee costs nothing while the portfolio is run prudently, and the discipline it imposes, treating the company's debt as your own when you size it, is the discipline a good landlord runs on anyway. It is the honest price of the structure that delivers full interest deductibility and the 125% ICR, and on the numbers, it is usually a price worth paying. The wider context sits in our guides to buy-to-let through a limited company and the limited company buy-to-let mortgages we arrange across the UK.
If you mean a company mortgage supported by your personal guarantee: yes, that is exactly how limited company buy-to-let works. The company borrows, and the directors' guarantees stand behind the loan. If you mean using someone else's guarantee to support your own personal mortgage, that is the separate (and now rare) guarantor mortgage market, which is regulated lending and not what this guide covers. On company buy-to-let, the guarantee is not an obstacle to the mortgage; it is a standard condition of it.
A legally binding promise by an individual, normally a director or significant shareholder, to repay the company's debt personally if the company does not. On a limited company mortgage it means that although the company owns the property and owes the loan, the lender can pursue the guarantors' personal assets for any shortfall after the property is sold. It is the lender's answer to limited liability, and it converts "the company's problem" into "your problem" to the extent of the guaranteed amount.
There is no "3 7 3 rule" in UK mortgage or company lending; the phrase circulates online without any statutory or market basis, and no lender we place business with uses it. The guarantee terms that genuinely matter are scope (what is guaranteed), cap (how much), duration (until when, and whether it is released on refinance), and whether liability is joint and several between guarantors. Judge any guarantee document on those four, with independent legal advice.
No harder than a personal buy-to-let when the case is packaged properly, and the affordability test is actually friendlier: lenders stress company applications at a 125% interest cover ratio rather than the 145% applied to higher-rate individuals. What the company route adds is process, SIC codes, deposit documentation, and personal guarantees with independent legal advice, which is paperwork rather than difficulty. Cases that struggle usually have a fixable defect: wrong SIC codes, undocumented deposits, or adverse credit on a director.
This guide is general information about non-regulated company lending, not legal advice: the independent solicitor who reviews your guarantee is the right source for advice on your specific document.
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