Personal Guarantees on Company BTL

A deed of guarantee is the document a limited company buy-to-let lender asks its directors to sign alongside the mortgage itself, promising to personally cover the debt if the company cannot pay. It sits outside the mortgage deed, but it is not optional paperwork: almost no mainstream lender will offer a company (SPV) buy-to-let mortgage without one, and it is the single biggest reason limited liability does not fully protect a director from a company mortgage going wrong.

This guide explains what a deed of guarantee actually commits you to, why lenders insist on one, what happens if the company defaults, and the practical steps worth taking before you sign.

What a deed of guarantee is

When a limited company borrows against a property, the mortgage is a debt of the company, not of its directors or shareholders personally. A deed of guarantee changes that in one specific respect: it gives the lender a separate, direct right to pursue a named director personally for the mortgage debt if the company fails to pay, as though the debt had been theirs from the start.

The guarantee is usually signed by every director with a meaningful shareholding, sometimes every director regardless of shareholding, and occasionally a spouse or other connected party the lender wants comfort from as well. It typically covers the full mortgage balance, plus interest, costs and any shortfall left after the lender has sold the property to recover what it can, not just a token or partial amount.

Why lenders require one

Lenders like the tax and structural benefits a limited company gives a director, but from a credit risk perspective, a company set up purely to hold one or two rental properties is a thin borrower with no trading history, no other assets, and no track record of managing debt. If the property alone does not cover the loan on a forced sale, there is nothing else inside the company to fall back on.

A personal guarantee closes that gap by giving the lender access to the director's wider personal position, income, other assets and credit history, in exactly the same way a personal-name buy-to-let mortgage would. It does not remove the tax and administrative reasons for using a company; it simply means the protection a limited company gives you against most other business debts does not extend to this one. Our limited company buy-to-let mortgage guide sets out how personal guarantees fit alongside the wider lending criteria for SPV borrowing.

What you are actually agreeing to

A few features of a typical deed of guarantee catch first-time company landlords off guard:

• Joint and several liability. If there are two or more directors, the lender can usually pursue any one of them for the full outstanding amount, not just their proportionate share, leaving the guarantors to sort out contributions between themselves afterwards.
• It survives beyond the mortgage term. The guarantee generally remains in force until the mortgage is fully repaid or formally released, regardless of whether a director later resigns, sells their shares, or leaves the business, unless the lender specifically agrees to release them.
• It can extend to related lending. Some guarantees are drafted to cover not just the specific mortgage but any other borrowing the company has, or later takes on, with the same lender, so it is worth checking the exact wording rather than assuming it is limited to a single loan.
• Death or serious illness does not automatically discharge it. A guarantor's estate can remain liable, which is worth factoring into life insurance and estate planning conversations, not just the mortgage application itself.
• It is separate from any deposit funding arrangement. Whether your deposit was paid in as a director's loan or share capital, the guarantee is a distinct obligation covering the mortgage debt, not the money you put into the company to fund the purchase. Our director's loan account guide covers how deposit funding into a company is normally structured and repaid.

Independent legal advice

Most lenders require each guarantor to take independent legal advice before signing, from a solicitor who is not acting for the lender or the company on the same transaction, and to provide a signed certificate confirming that advice was given. This is not a box-ticking formality on the lender's side: it exists precisely because a personal guarantee is a serious commitment, and the lender wants documented evidence that each director understood what they were signing rather than being able to claim later that they did not.

Use that advice properly. Ask specifically what happens if the company defaults, whether the guarantee extends beyond this one mortgage, and what your realistic personal exposure looks like against your own income, savings and other assets, not just against the property itself.

Practical steps before signing

• Read the guarantee alongside the mortgage offer, not after it. The headline rate and terms in a mortgage offer do not tell you the scope of the personal exposure sitting behind it.
• Ask whether the guarantee is limited or unlimited. Some lenders will negotiate a cap, particularly for a director with a smaller shareholding, though many standard SPV products only offer an unlimited guarantee as a condition of lending.
• Check how co-director liability works in practice, particularly if shareholdings are unequal, so an agreement between directors on how any shortfall would be shared sits alongside the lender's own joint and several terms.
• Factor the guarantee into your own risk picture, alongside the property's rental cover and your personal financial position, rather than treating the mortgage as purely a company matter once it is signed. Our SPV versus personal ownership guide compares the wider trade-offs of buying through a company, including this one.
• Keep a record of every guarantee you have signed, especially once you hold more than one company-owned property, since each new mortgage typically brings its own separate guarantee rather than one blanket document covering the whole portfolio.

Common mistakes

The most common misunderstanding is assuming limited liability protects a director from the mortgage itself. It protects you from most other company debts and claims, but the personal guarantee is a deliberate, specific carve-out from that protection, agreed to in writing rather than imposed automatically.

A second common mistake is treating the guarantee as a formality because "the company will always cover the payments." Companies fail, rents fall, and void periods happen. The guarantee only ever becomes relevant when the company cannot pay, which is exactly the scenario where a director is least prepared to also find the money personally, so it is worth planning for that possibility rather than assuming it away. Landlords with more than one director should also confirm, in writing between themselves, how any shortfall would be shared, since the lender's joint and several right does not settle that question for you; it only settles who the lender can pursue.

How PropMaps helps

PropMaps tracks every mortgage in your portfolio, including which properties are held through a limited company, their lender, rate and fixed-rate end date, so if you are weighing up another company purchase and the guarantee that comes with it, you can see your existing exposure across the whole portfolio in one place rather than piecing it together from separate mortgage offers. See our guide on how much deposit you need for buy-to-let for how company deposits typically compare with personal-name purchases.

Disclaimer

This guide is general information for UK landlords, not legal or financial advice. Personal guarantees are binding legal documents with serious consequences. Take independent legal advice from a solicitor before signing one, and check the specific terms with your lender.