Do you pay SDLT when transferring more of a mortgaged buy-to-let property to your spouse?

Introduction

People often ask whether Stamp Duty Land Tax (SDLT) is triggered when one spouse gives the other a larger share in a rental property, especially where no money changes hands. The confusion usually arises because SDLT can still apply if the property is subject to a mortgage. The key question is whether the spouse receiving the extra share is also taking on more of the mortgage debt, and if so, how much.

This article explains the SDLT position where a married couple already own a buy-to-let property jointly, and one spouse transfers most of their beneficial interest to the other for income tax planning purposes.

The Question

A married couple live together in a main home owned by one spouse. They also jointly own a buy-to-let property, currently on a 50:50 basis, and that property has an outstanding mortgage of about £224,000.

They plan to sever the joint tenancy and change the beneficial ownership so that one spouse holds 95% and the other 5%. No cash will be paid. The transfer is intended to be a gift, but the spouse receiving the larger share will effectively take on a greater share of the mortgage debt.

The questions are:

• Does SDLT arise on the transfer?
• If no SDLT is payable, does an SDLT return still need to be filed?
• Do the higher rates for additional dwellings apply?

Nick’s Explanation

Nick’s explanation can be summarised like this:

Where a share in mortgaged property is transferred and no money is paid, SDLT is not calculated by reference to the market value in an ordinary spouse-to-spouse gift case. Instead, the relevant chargeable consideration is usually the amount of mortgage debt taken on by the receiving spouse.

On the figures given:

• Outstanding mortgage: £224,000
• Current assumed share of debt at 50%: £112,000
• New assumed share of debt at 95%: £212,800
• Increase in debt assumed: £100,800

Nick’s view was that the chargeable consideration would be £100,800, being the additional mortgage liability taken on. As that figure is below the current residential SDLT nil-rate threshold of £250,000, no SDLT would be payable at standard residential rates.

He also explained that, because the transaction is between spouses living together, the higher rates for additional dwellings are generally disapplied in this kind of transfer.

However, because the chargeable consideration exceeds £40,000, the transaction remains notifiable, so an SDLT return would still need to be submitted to HMRC within the filing deadline, even though no tax is due.

The Law

SDLT is charged on land transactions under the Finance Act 2003.

The main provisions relevant here are as follows:

• Finance Act 2003, section 42: SDLT is charged by reference to chargeable consideration.
• Finance Act 2003, Schedule 4, paragraph 8(1)(b): where the purchaser assumes existing debt secured on the property, that assumed debt counts as chargeable consideration.
• Finance Act 2003, section 77: certain land transactions must be notified to HMRC by filing an SDLT return.
• Finance Act 2003, section 77A and related provisions: a transaction is generally notifiable if chargeable consideration is £40,000 or more, subject to the detailed statutory rules.
• Finance Act 2003, Schedule 4ZA: this contains the rules for the higher rates for additional dwellings.

For spouse and civil partner transactions, Schedule 4ZA includes special rules. Broadly, where spouses are living together, a transfer between them is not generally caught by the higher rates rules in the same way as an ordinary acquisition of an additional dwelling by an unconnected buyer.

Analysis

The SDLT analysis can be worked through in stages.

First, changing beneficial ownership between spouses can still amount to a land transaction for SDLT purposes. The fact that it is a gift does not automatically mean SDLT is irrelevant.

Second, if the property is mortgage-free and no money is paid, there may be no chargeable consideration at all. But where the property is subject to a mortgage, the spouse receiving the larger share may also be treated as assuming a larger share of that secured debt.

Third, on these facts, the spouse moving from 50% ownership to 95% ownership increases their share of the mortgage burden from £112,000 to £212,800. The increase is £100,800. That increase is the chargeable consideration for SDLT purposes.

Fourth, if the residential nil-rate threshold is £250,000 at the effective date of the transfer, a chargeable consideration of £100,800 falls below that threshold. That means SDLT is charged at 0%, so no tax is payable.

Fifth, the higher rates question needs to be considered separately. A buy-to-let property is an additional dwelling, so this is often where people worry about a 3% surcharge. However, the special spouse rules are important. In a transfer between spouses living together, the higher rates rules are generally switched off for this purpose. On that basis, the transfer should not attract the higher rates surcharge.

Sixth, even where no SDLT is payable, a return can still be required. If the chargeable consideration is £40,000 or more, the transaction is generally notifiable. Here, the consideration is £100,800, so an SDLT return should still be filed.

One practical point is that the legal and beneficial ownership structure should be implemented properly. If the couple are changing from joint tenancy to unequal beneficial shares, that is usually done by severing the joint tenancy and recording the new beneficial interests in an appropriate declaration or deed, with lender consent where required.

Outcome

On the facts described, the likely outcome is:

• No SDLT is payable, because the chargeable consideration is the additional mortgage debt assumed, calculated at about £100,800, which is below the £250,000 threshold.
• The higher rates for additional dwellings should not apply to this spouse-to-spouse transfer while the couple are living together.
• An SDLT return should still be filed because the chargeable consideration exceeds £40,000.

Practical Steps

If you are assessing a similar transfer, the sensible steps are:

1. Confirm the current outstanding mortgage balance at the date of transfer.
2. Work out the old and new beneficial ownership percentages.
3. Calculate the increase in mortgage debt being assumed by the receiving spouse.
4. Check the residential SDLT thresholds in force on the effective date of the transaction.
5. Consider whether the spouse exemption from the higher rates rules applies, which usually depends on the couple being married or in a civil partnership and living together.
6. Ensure the ownership change is documented correctly, including severance of joint tenancy if relevant.
7. Check the mortgage terms and obtain lender consent if required.
8. File the SDLT return on time if the transaction is notifiable, even where no tax is payable.

If the transaction also forms part of wider income tax planning, it is also worth checking whether a Form 17 election is relevant. That is a separate issue from SDLT and depends on the legal and beneficial ownership arrangements actually put in place.

Conclusion

Where one spouse gives the other a larger share in a mortgaged buy-to-let property, SDLT is usually based on the extra mortgage debt taken on, not on the full value of the gifted share. In the example considered here, that produces chargeable consideration of about £100,800, so no SDLT would be payable at current standard residential rates. Even so, an SDLT return would still normally be required because the consideration exceeds £40,000.

Legal References Used

• Finance Act 2003, section 42
• Finance Act 2003, section 77
• Finance Act 2003, Schedule 4, paragraph 8(1)(b)
• Finance Act 2003, Schedule 4ZA

This page was last updated on 22 March 2026.

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