Gazumping is a seller accepting a higher offer after already accepting yours. Gazundering is a buyer dropping their offer just before exchange. Both are possible in England and Wales for one reason: nothing is binding until contracts are exchanged.
What actually reduces the risk
| Action | What it protects against | Honest assessment |
|---|---|---|
| Get your mortgage agreed in principle first | Delay, which is what creates the window | The single most effective step |
| Instruct a solicitor before you offer | Weeks of dead time at the start | Cheap and effective |
| Ask the seller to take the property off the market | Casual gazumping | No legal force, but it sets an expectation |
| Lock-out or exclusivity agreement | A seller negotiating with others for a fixed period | Costs money; used mainly on higher-value deals |
| Home buyer protection insurance | Wasted survey and legal fees if it collapses | Covers your costs, not the house |
There is no way to make an accepted offer binding short of exchanging contracts. Anyone selling you certainty before exchange is selling you a cost-recovery product, which is worth having but is not the same thing.
Speed is the real defence. Almost every gazumping story has weeks of avoidable delay in the middle of it.
Sources
Related
- What "sold subject to contract" really means
- Why do property sales fall through?
- How long does conveyancing take?
Last reviewed: 2026-09-20. We check these against the linked official sources and re-date the page when they change.