When a property contract counts as completed for stamp duty
Completion under an SDLT contract
For this SDLT rule, completion means carrying out the proposed deal between the same parties and in substantial conformity with their contract.
- Any agreement can be a contract.
- Compare the contract with the final transfer.
- Changes to parties or terms can matter.
Scroll down for the full analysis.
Read the original guidance here:
When a property contract counts as completed for stamp duty
For stamp duty land tax (SDLT), “completion” involves more than signing the final paperwork: the same people must carry out the proposed property deal, and the completed deal must closely match the contract. That can affect when SDLT is due.
What this rule is about
Section 44 deals with a property deal that begins with a contract and that a transfer later completes. It also covers “substantial performance” where, before completion, a party takes possession, makes a major payment, or otherwise performs a significant part of the agreed transaction. That matters.
The definitions provide the framework for deciding whether that later step actually completes the earlier deal.
What the official source says
Under the law, the same parties must complete the deal in substantial conformity with the contract. HMRC’s manual also explains the terms used in this rule.
- A contract can be any agreement.
- Completion must carry out the proposed property deal.
- Both the buyer and seller must be the same people.
- The completed deal must closely match the contract.
- HMRC says that a conveyance includes any instrument, including electronic documents and leases.
What this means in practice
The original contract is not automatically completed merely because a final transfer occurs. A different buyer, seller, or a major change to the deal can matter. This is the part people often miss.
- Keep the signed contract and later transfer together.
- Check whether either party changed before the final step.
- Check whether the property or rights transferred changed.
- Record any variation the parties agree after the contract.
How to analyse it
Begin with the documents themselves rather than the labels attached to them. Then ask whether the final step carries out the deal the parties originally agreed.
- Identify the agreement that created the proposed deal.
- Identify the parties to that agreement.
- Read the final transfer, lease, or other instrument.
- Compare the parties, property, and main terms.
- Consider whether possession or payment happened earlier.
Example
Illustration: Maya agrees to buy a shop for £250,000. Here, Maya and the seller complete the later transfer and carry out that agreed sale, so the transfer meets the definition of completion. If the shop is instead transferred to a different buyer, or the deal changes in a major way, the answer may differ. The wording calls for a close comparison.
Why this can be difficult in practice
Small changes may be harmless, while larger changes may mean the final step is not completion of the original contract. The law gives no fixed checklist for “substantial conformity”.
- A new party can be a key change.
- Later side agreements may alter the original deal.
- Possession or payment before completion can raise a separate timing question.
Key takeaways
- The same parties must complete the deal.
- The final deal must closely match the contract.
- An agreement need not use the word “contract”.
Technical analysis
For advisers, and for anyone who wants to check the law behind this page. You do not need this section to understand the guidance above.
Legislation
- FA 2003 section 44 — contracts, substantial performance and completion for SDLT
Official guidance
The pages below are HMRC’s guidance. Guidance is not law. It sets out how HMRC reads the legislation, and it is not binding on you, on a tribunal or on a court. Where guidance and the legislation differ, the legislation wins. HMRC can also change or withdraw guidance, and it may not cover your facts.
Where this is not settled
- It may be unclear whether a changed deal remains in substantial conformity with the original contract.
Evidence you would need
This kind of case is decided on the facts of the individual property. These are the records that usually settle it, and the ones an adviser would ask you for.
- The contract or agreement and any amendments.
- The final transfer, lease or other instrument.
- Evidence of the parties involved at each stage.
- Dates and evidence of possession or payments where substantial performance may matter.
Explore this with an AI
Readers often want to test their own situation. Copy the prompt below into ChatGPT, Claude or Gemini. It hands the model the actual legislation for this page rather than letting it answer from memory, and tells it to be explicit about what is uncertain. What comes back is information, not advice – check it against the links above.
I am researching UK Stamp Duty Land Tax (SDLT), which applies in England and Northern Ireland. MY QUESTION When a property contract counts as completed for stamp duty [Replace this with your own situation: what you are buying, the price, the dates, who the buyer is, and what you plan to do with the property.] THE LAW THIS TURNS ON - FA 2003 section 44 - contracts, substantial performance and completion for SDLT https://www.legislation.gov.uk/ukpga/2003/14/section/44/2025-11-17 Guidance page from HMRC on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm08100 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. Guidance from HMRC is its view of the law, not the law, and does not bind a tribunal or a court. 2. Tell me what the rule actually requires, in plain English. 3. Tell me which facts decide the answer, and which facts would change it. 4. Tell me what evidence I would need to support the position. 5. Be explicit about anything unsettled or fact-sensitive. Do not guess. 6. Your training data has a cutoff and SDLT rates and reliefs change at fiscal events. Say so if you are not sure the law is current. POINTS ALREADY KNOWN TO BE UNCERTAIN ON THIS TOPIC - It may be unclear whether a changed deal remains in substantial conformity with the original contract. Do not give me a conclusion you cannot support from the provisions above.
Legislation links show Finance Act 2003 as it stood on 2025-11-17. The law may have changed since, and the rules that apply are those in force on the date of your transaction. The official guidance this page is based on is here.
This page was last updated on 31 August 2026
Useful article? You may find it helpful to read the original guidance here: When a property contract counts as completed for stamp duty
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