Example 10: Tax Implications of Multiple Dwelling Relief on Property Sales

Multiple Dwellings Relief and Later Combining of Houses

If a buyer claims multiple dwellings relief (MDR) on buying several homes, later combining some of those homes into fewer dwellings can trigger a recalculation of SDLT within the relevant period. Whether this affects the original MDR claim depends mainly on whether the properties had already been sold, and if so, whether they were sold to an unconnected third party or to a connected person.

• MDR is based on the number of dwellings bought, so a later merger of homes into one can reduce that number and lead to a clawback of relief.
• If a dwelling is sold to an unconnected third party, the relevant period ends for that dwelling, so later changes by that buyer do not affect the original MDR claim.
• If a dwelling is sold to a connected person, the relevant period may continue, so a later merger by that connected buyer can still affect the original purchase.
• In HMRC’s example, buying six houses was later recalculated first on the basis of five dwellings, then four, as further relevant mergers took place.
• The SDLT position may need to be reviewed more than once during the relevant period if there are several later events.

Scroll down for the full analysis.

Multiple dwellings relief: what happens if houses are later combined after purchase

This page explains how multiple dwellings relief can be affected if a buyer acquires several dwellings and, within the relevant period, some of those dwellings are later combined into fewer dwellings. The source material is an HMRC manual example. Its main point is that later events do not always affect the original relief in the same way. Much depends on whether a dwelling has already been sold, and if so, whether it was sold to a connected or unconnected person.

What this rule is about

Multiple dwellings relief reduces SDLT by calculating tax on the average price per dwelling, subject to the minimum rate rules that apply. Because the relief depends on the number of dwellings acquired, later changes can matter if they mean the original transaction should no longer be treated as involving that number of dwellings.

The legislation contains a clawback mechanism for certain events happening within a set period after the purchase. One of those events is where dwellings are combined so that there are fewer dwellings than at the time of the original acquisition. HMRC’s example shows how that rule works where some properties have already been sold on before the combination happens.

What the official source says

The example starts with one individual buying the freehold of six semi-detached houses.

He then disposes of them in stages:

• After six months, he sells two houses to an unconnected third party, who combines them into one.
• After another six months, he sells another two houses to his wife, who combines them into one.
• After a further six months, he combines the last two houses into one and sells that to an unconnected third party.

HMRC says the first sale is not a relevant event for the clawback rule. Because the sale is to an unconnected third party, the relevant period ends for those houses. So when that buyer later combines them into one, that later combination does not affect the original buyer’s relief.

The second sale is also not itself a relevant event. But because the sale is to a connected person, the relevant period does not end for those houses. So when the wife later combines those two houses into one, that combination does count as a relevant event for the original purchase.

At that point, the tax is recalculated on the basis of five dwellings. HMRC’s reasoning is that the original six dwellings are now treated as reduced by one, because the wife’s two houses have become one, while the two earlier sold to the unconnected third party still count as two for this purpose.

When the original buyer later combines his remaining two houses into one, that is another relevant event. HMRC says the tax is then recalculated on the basis of four dwellings: the two houses already sold to the unconnected third party, plus the two newly combined dwellings.

Finally, the sale of that last remaining property to an unconnected third party brings the relevant period fully to an end, eighteen months after the original transaction.

What this means in practice

The key practical point is that a later physical change to a property can still affect the original MDR claim even if the original buyer no longer owns that property. The question is whether the relevant period has ended for that property.

If a dwelling is sold to an unconnected third party, the relevant period ends for that dwelling. After that, what the third party does with it does not feed back into the original buyer’s MDR calculation.

If a dwelling is sold to a connected person, the relevant period does not end in the same way. So if that connected person later combines dwellings, the original buyer may face a recalculation of SDLT and a clawback of some of the relief.

This means connected-party transfers need particular care. A sale that looks like an ordinary disposal may leave the original MDR position exposed if the connected buyer later changes the dwelling count.

How to analyse it

A sensible way to approach this kind of case is to ask the following questions.

• How many dwellings were acquired in the original transaction for MDR purposes?
• Has anything happened within the relevant period that reduces that number, such as two dwellings being combined into one?
• If a property was sold on before the combination, was the sale to an unconnected third party or to a connected person?
• Did that sale bring the relevant period to an end for that property?
• After taking those points into account, how many dwellings should the original transaction now be treated as involving?

The HMRC example also shows that the recalculation may need to be done more than once if there are several later events during the relevant period.

Example

Illustration: a buyer claims MDR on buying six houses. He later sells two to an independent buyer, who merges them into one home. That merger does not affect the original MDR position, because those houses had already left the relevant period when sold to an unconnected person.

He then sells another two to his spouse, who also merges them into one home. This does affect the original MDR position, because the connected-party sale did not close the relevant period for those houses. The original purchase is then revisited on the basis that there are now five dwellings rather than six.

If the buyer then merges his own remaining two houses into one, the original purchase is revisited again, this time on the basis of four dwellings.

Why this can be difficult in practice

The difficult part is not usually spotting that dwellings have been combined. It is working out whether that later combination still matters for the original buyer’s MDR claim.

The answer depends on the interaction between three separate ideas:

• what counted as a dwelling at the date of purchase,
• whether a later event falls within the statutory clawback rules, and
• whether a disposal to another person has ended the relevant period for that property.

Connected-party sales are especially easy to misread. A person might assume that once the property has been sold, later works by the buyer are irrelevant. HMRC’s example shows that this is not always true. If the sale is to a connected person, later combination can still feed back into the original acquisition.

Another practical difficulty is timing. The position may change more than once during the relevant period, so the SDLT consequences may need to be revisited at each stage rather than only once at the end.

Key takeaways

• A later combination of dwellings can reduce the number of dwellings used for the original MDR calculation.
• A sale to an unconnected third party can end the relevant period for those dwellings, so later changes by that buyer do not affect the original relief.
• A sale to a connected person does not necessarily protect the original MDR claim from later clawback if the dwellings are then combined.

This page was last updated on 24 March 2026

Useful article? You may find it helpful to read the original guidance here: Example 10: Tax Implications of Multiple Dwelling Relief on Property Sales

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