An exchange deposit is part of the total amount that must be paid when exchanging contracts and this adds up to 10% of the property's purchase price - it will not be refunded if something goes wrong with the transaction. To put it into context, let us say that you are paying a 15% deposit; initially, 10% (the exchange deposit) should come out from your pockets while the remaining 5%, will be needed at completion time. However, there is an exemption here: if you obtained a 95% mortgage then all 5% needs to go as soon as exchanging contracts happen.