Exchange, completion and what changes at each moment

The options around exchange and completion are set out side by side below, with the conditions that genuinely favour one over the other.

Two events, two functions

Exchange creates a binding contract to buy and sell on a stated date; completion performs it. Splitting them lets both parties arrange finance, removals and a chain around a fixed known date. Some jurisdictions bind much earlier, at the point of a signed offer or a notarial preliminary contract, and some complete almost immediately.

The names differ; the function of a binding moment followed by a transfer moment recurs widely.

What happens at exchange

A deposit is usually paid, contracts are formally exchanged and a completion date is fixed. Withdrawal after this point typically means losing the deposit and potentially further damages. In many systems risk in the property passes at exchange, meaning the buyer should have buildings insurance in force from that day.

In practice, this is a frequently missed step, and a fire between exchange and completion is precisely what it protects against.

The gap between the two

The gap is negotiated and is commonly a small number of weeks, long enough to arrange removals and short enough to limit risk. Simultaneous exchange across a chain is coordinated by the conveyancers, which is why one unresponsive party delays everyone.

Nothing prevents same-day exchange and completion, and it removes the safety margin for arranging everything else. A long gap increases the chance that a mortgage offer expires or circumstances change.

What happens at completion

Funds are transferred, the seller conveyancer confirms receipt, the keys are released and the transfer document takes effect. Any mortgage on the seller side is redeemed from the proceeds and the discharge is registered afterwards. Registration of the new ownership follows and can take weeks or months depending on the jurisdiction.

Apportionments for service charges and local taxes are settled through the completion statement.

Things that go wrong on the day

Late funds transfers, a bank cut-off time missed, or one party in a chain not ready can delay completion by a day, with contractual consequences. Sellers occasionally leave the property in an unexpected state or remove items that were included, which is far harder to remedy after completion.

A final inspection before completion, where permitted, catches this while you still have leverage. Keep the removal booking flexible where possible, since a delayed completion with a van outside is expensive.

None of this is a substitute for talking to a clinician if something feels wrong.

Fraud risk at the money stage

Payment redirection fraud targets the moment large sums move, usually by emailing revised bank details. Conveyancers will normally confirm that they never change account details by email, and verifying by telephone on a known number is the standard defence. Send a small test payment first where your conveyancer supports it.

This is general information; your conveyancer sets the procedure for your specific transaction.

Side by side

The takeaway

Know which moment binds you, insure from that moment, and verify bank details by phone before any transfer.

Pick the one that costs you least, and let the rest wait.