Gazumping

When a seller accepts a higher offer from another buyer after verbally agreeing to your offer but before contracts exchange.

Gazumping is the practice of a seller accepting a higher offer from a second buyer after having verbally agreed to sell to the original buyer — possible because no contract is binding until both parties sign and exchange. It's legal but considered unethical, and more common in rising markets. The buyer typically loses any costs already spent on inspections and conveyancing. NSW briefly considered legislating against it in 2017; no state has.