What is a fee called that is added to the final bid at some auctions to determine the actual selling price?

The fee that is added to the final bid to determine the actual selling price at an auction is known as the buyer's premium. This premium is a percentage of the winning bid, and it is added to that bid to calculate the total amount the buyer will pay. The buyer's premium serves to compensate the auction house for its services and operational costs associated with conducting the auction.

In many auctions, this fee is clearly disclosed to participants beforehand, allowing buyers to understand the total financial commitment required should they successfully win an item. The inclusion of a buyer's premium is a common practice in the auction industry and helps to cover the auctioneer's costs while also potentially enhancing the revenue generated from the auction.

Other terms like absolute premium, bona fide fee, and sales tax do not accurately represent this additional charge. While sales tax is a government-mandated tax applied to the sale of goods, it is separate from the buyer's premium, which is a fee set and collected by the auction house itself.