What are exchange and completion?
Exchange of contracts is the point at which a sale becomes legally binding, usually with a deposit paid. Completion is when the money is transferred and ownership passes to the buyer; for tenanted property, the buyer becomes the landlord from that date.
Read more in our guide: Portfolio sale timescales
Key facts at a glance
| Item | Detail |
|---|---|
| Exchange of contracts | The sale becomes legally binding; the buyer usually pays a deposit, traditionally 10% |
| If the buyer pulls out after exchange | They normally lose their deposit and may face a claim for further losses |
| If the seller pulls out after exchange | The buyer can sue for breach of contract or ask the court to enforce the sale |
| Completion | The balance is paid, keys are released and ownership passes, usually by early afternoon |
| Gap between the two | Anything from same day to several weeks, often 1 to 4 weeks |
| Date of disposal for CGT | Exchange (the 60-day reporting clock runs from completion) |
| After completion | The buyer's solicitor pays SDLT within 14 days and registers the transfer at HM Land Registry |
Exchange of Contracts
Until contracts are exchanged, either side can walk away without penalty, which is why price renegotiations and failed sales happen in the weeks before exchange. At exchange, the solicitors for both sides confirm by phone that the signed contracts are identical, insert the agreed completion date and treat the contracts as exchanged. The buyer's deposit is then paid, commonly 10%, though 5% is often agreed.
Before exchanging, a seller should be satisfied that the buyer has the funds, that any mortgage redemption figures are known, and, if the contract promises vacant possession, that the property will be empty in time.
Completion
On completion day, the buyer's solicitor sends the balance of the price to the seller's solicitor, who redeems the seller's mortgages, pays the agreed fees and sends the rest to the seller. Ownership passes and the buyer can collect the keys. For a tenanted sale, the buyer becomes the landlord from that moment. Rent for the current month is apportioned on the completion statement and the deposits are dealt with as agreed in the contract.
Exchange and Completion in a Portfolio Sale
- One exchange or several. A block sale usually has one contract and one completion for every property. A phased sale can exchange once with staged completions, or exchange in stages.
- Tax year timing. Because CGT treats exchange as the date of disposal, exchanging on 4 April or 7 April can put the gain in different tax years. Agree the timetable with your accountant first.
- Lenders. Each mortgage must be redeemed on completion. Ask for redemption statements early, especially where several lenders are involved, and check early repayment charges.
- Simultaneous exchange and completion is common with cash buyers, but leaves no binding period, so the deal is not certain until the money arrives.
A Typical Sequence
- Offer agreed and solicitors instructed.
- ID and AML checks, contract pack and searches.
- Enquiries raised and answered.
- Buyer's finance and survey confirmed.
- Contracts signed and exchanged, deposit paid.
- Completion on the agreed date.
- Seller files the 60-day CGT return; buyer files SDLT and registers.
Official Sources and Further Reading
General information for landlords in England, checked against official sources in October 2026. It is not tax, legal or financial advice: speak to a qualified accountant or solicitor about your own circumstances.
Frequently Asked Questions
Exchange of contracts is the point at which a sale becomes legally binding, usually with a deposit paid. Completion is when the money is transferred and ownership passes to the buyer; for tenanted property, the buyer becomes the landlord from that date.
Exchange is when the contract becomes legally binding and a deposit is paid. Completion is when the full price is paid and ownership passes to the buyer.
It is agreed between buyer and seller. It can be the same day, but one to four weeks is common.
Only by breaching the contract. They would normally lose their deposit and could be liable for the seller's further losses.
For an unconditional contract, the date of exchange is the date of disposal for CGT. The 60-day deadline to report and pay runs from completion.
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