Gazumping happens when a seller who has already accepted one buyer's offer then goes on to accept a higher offer, pushing the first buyer out of the picture.
It can come about at any point before contracts are exchanged, as until the papers are signed there is no legal obligation to either buy or sell.
The first buyer stands to lose out on the property of his or her dreams, but that's not the only problem. They can also lose money. If surveys, searches and fees have already been incurred, they cannot then be recouped.
The seller's estate agent is legally obliged to inform them of any offers made on their property, and it is up to the seller whether or not they consider them.
If the seller wants the property to be removed from the estate agent's register, he or she must make the request in writing, and some sellers prefer not to do so until the contracts are signed.
Exclusivity agreements can help to avoid gazumping. These involve the seller signing an agreement that states that during a specified exclusivity period, he or she will not enter into any agreement with anyone else.
Some insurance companies offer gazumping insurance policies to cover fees you might have incurred.
Gazundering is a phenomenon more common to a buyers market.
This is where the buyer gets to be mean to the seller by waiting until everybody is poised to exchange contracts and then lowering his or her offer on the property.
If the seller refuses, the whole chain might collapse.