What is the fee added at the end of an auction commonly referred to as?

The fee added at the end of an auction is commonly referred to as the buyer's premium. This is a percentage of the final auction price that is added to the winning bid, and it is paid by the buyer. The buyer's premium serves to cover the costs associated with conducting the auction, such as the auction house's overhead, marketing, and other administrative expenses. This charge is standard practice in auction settings, ensuring that the auction house receives compensation beyond the bids placed during the event. By clearly identifying this fee, participants can understand the total cost they will incur for their purchases, which is an essential element of transparency in the auction process.