The terms, defined
Gazumping is when a seller accepts your offer but then accepts a higher offer from someone else before contracts are exchanged, leaving you out. Gazundering is the reverse: a buyer lowers their offer at the last minute, usually just before exchange, gambling that the seller is too committed to refuse.
Both are possible because, in England and Wales, nothing is legally binding until exchange of contracts. Until that moment, either party can change their mind or their price with no penalty.
Why the system allows it
The gap between offer acceptance and exchange — often weeks — is when searches, surveys and mortgage arrangements happen. Throughout that period the deal is 'subject to contract', and it's that long, non-binding window that creates the opportunity to gazump or gazunder. Scotland's system, where offers become binding earlier, largely avoids gazumping.
This is exactly what the government's 2026 home-buying reform roadmap sets out to change in England: a move towards binding conditional contracts that commit both sides earlier, with penalties for pulling out without a legitimate reason. It's phased and not yet law, but the direction is clear — and it makes doing your diligence before you offer more important than ever. See our guide to the binding-contracts reform for what's coming and how to prepare.
How to reduce the risk of being gazumped
Move fast and be visibly serious: have your mortgage agreement in principle ready, instruct a conveyancer immediately, and keep the chain moving so there's less time for a rival to appear. Build a good rapport with the seller — people are less likely to gazump a buyer they like and trust.
Ask the seller to take the property off the market on acceptance, and consider a lock-out (exclusivity) agreement that legally prevents them negotiating with others for a set period. Some buyers also use home-buyer protection insurance to recover wasted costs if a purchase collapses through no fault of their own.
Reducing the risk of being gazundered
As a buyer you can't be forced up, but as a seller you can reduce gazundering risk by pricing realistically, keeping momentum, and not letting the process drift towards exchange over many months. A buyer who has done their diligence up front is also less likely to discover a late surprise that 'justifies' a reduced offer.
Doing your homework before you offer — understanding the property's flood, planning, title and price-paid position early — means fewer late shocks, a faster path to exchange, and less exposure to either tactic. That's the case for front-loading diligence with a pre-offer report.
Frequently asked questions
Is gazumping legal?
Yes. Until contracts are exchanged, a seller is free to accept a better offer. It's frustrating but not unlawful in England and Wales.
Can I get my money back if I'm gazumped?
Not from the seller by default. You'll usually have spent on searches, survey and legal work. Home-buyer protection insurance can cover some wasted costs if you took it out beforehand.
Does a lock-out agreement guarantee the sale?
No — it only stops the seller negotiating with others for a fixed period; it doesn't force completion. But it buys you protected time to get to exchange.