Understanding SDLT Chargeability: Contracts, Substantial Performance, and Effective Dates Explained

When SDLT is charged on a land contract

Signing a contract to buy or lease land does not usually trigger SDLT on its own. The normal rule is that SDLT is charged on completion, but if the contract is substantially performed before then, SDLT can arise earlier and that earlier date becomes the effective date for SDLT purposes.

• FA 2003 section 44 says a contract intended to be completed later by conveyance is normally taxed on completion, not when it is signed.
• Substantial performance can happen before completion if any rent is paid, most of the non-rent price is paid, or the buyer takes possession of all or substantially all of the property.
• If substantial performance happens first, the contract is treated as the relevant transaction and the date of substantial performance becomes the effective date.
• In practice, exchange of contracts alone is not enough; you must check what has actually happened, such as early occupation, staged payments, or rent being paid.
• Some cases are fact-sensitive, especially whether the buyer has taken substantial possession or whether most of the price has been paid.

Scroll down for the full analysis.

When SDLT is charged on a contract: completion and substantial performance

This page explains an important SDLT timing rule. Simply signing a contract to buy or lease land does not usually trigger SDLT straight away. In most cases, SDLT is charged when the transaction is completed. But if the contract is substantially performed before formal completion, SDLT can arise earlier. That timing matters because it affects the effective date of the transaction and therefore when the return and tax position must be considered.

What this rule is about

FA 2003 section 44 deals with contracts for land transactions that are intended to be completed later by a conveyance or other formal completion step. The basic point is that a contract is not normally taxed just because it has been entered into.

Instead, the usual rule is that the chargeable transaction takes effect on completion. However, the legislation prevents parties from delaying SDLT simply by postponing formal completion after the buyer has already received the practical benefits of the deal.

That is where substantial performance comes in. If the contract has been substantially performed before completion, the contract is treated as if it were the transaction itself. The date of substantial performance then becomes the effective date for SDLT purposes.

What the official source says

The HMRC manual says that entering into a contract does not automatically create an SDLT liability. A contract that is to be completed by a conveyance is generally chargeable on completion.

The manual then explains that where the contract is substantially performed before formal completion, the contract is treated as the relevant transaction. In that situation, the effective date is the date of substantial performance.

The source describes substantial performance in broad terms. It is the point at which one of the following happens:

• any payment of rent is made
• most of the consideration other than rent is paid
• the purchaser takes possession of the whole, or substantially the whole, of the subject matter of the contract

The manual points to further guidance on the meaning of substantial performance and related definitions such as completion, conveyance and contract.

What this means in practice

The practical question is not just whether there is a signed contract. It is whether the buyer has already done enough, or received enough, for SDLT to be brought forward.

In an ordinary property purchase, parties may exchange contracts first and complete later. On those facts alone, SDLT is not normally triggered at exchange. The usual SDLT date is completion.

But the position changes if, before completion, the buyer:

• pays most of the purchase price, or
• goes into possession of all or substantially all of the property, or
• in the case of a lease, starts paying rent

Once substantial performance happens, SDLT timing moves forward. The contract is treated as the transaction for SDLT purposes, and the substantial performance date becomes the effective date.

This matters because SDLT rules often turn on the effective date. Even where the amount of tax is not discussed in this source, the timing point is critical within the wider SDLT framework.

How to analyse it

A sensible way to approach the issue is to ask these questions in order:

1. Is there a contract for a land transaction that is intended to be completed later by a conveyance or similar formal step?
2. Has formal completion actually happened? If yes, the normal rule is that completion is the chargeable point.
3. If completion has not yet happened, has the contract been substantially performed?
4. To answer that, check whether any rent has been paid, whether most of the non-rent consideration has been paid, or whether the purchaser has taken possession of the whole or substantially the whole of the property.
5. If one of those events has happened before completion, treat the substantial performance date as the effective date.

In practice, conveyancers and taxpayers should look carefully at what happened on the ground, not just what the contract says should happen later. Early access, occupation arrangements, licence wording, deposits, staged payments, and rental payments can all be relevant depending on the facts.

Example

Illustration: A buyer exchanges contracts to purchase a commercial building, with completion due two months later. Before completion, the seller allows the buyer to move into almost all of the building so that fitting-out works and business operations can begin. Even though legal completion has not yet taken place, the buyer may already have taken possession of the whole or substantially the whole of the subject matter of the contract. On the HMRC guidance summarised here, that would point towards substantial performance, so the SDLT effective date would move to the date possession was taken.

Why this can be difficult in practice

The source gives only broad indicators, not a complete code for every factual situation. Some cases are straightforward, but others are more judgment-based.

The main difficulty is often deciding whether the buyer has taken possession of the whole, or substantially the whole, of the property. That can be fact-sensitive. Limited access for inspections or preparatory works is not obviously the same as possession, and the source page does not try to define every boundary.

Another area of difficulty is deciding when “most” of the non-rent consideration has been paid. The source states the broad rule but does not set out detailed measurement issues on this page.

It is also important not to confuse exchange of contracts with substantial performance. Exchange by itself is not enough. Something more must happen before completion to bring section 44 into play in this way.

Finally, the manual is HMRC guidance on how the legislation operates. The legal effect comes from FA 2003, not from the manual alone. The manual is useful for understanding HMRC’s position, but the legislation remains the starting point.

Key takeaways

• Signing a contract does not usually trigger SDLT by itself.
• SDLT is generally charged on completion unless the contract is substantially performed earlier.
• If substantial performance happens first, that earlier date becomes the effective date for SDLT purposes.

This page was last updated on 24 March 2026

Useful article? You may find it helpful to read the original guidance here: Understanding SDLT Chargeability: Contracts, Substantial Performance, and Effective Dates Explained

View all HMRC SDLT Guidance Pages Here