A surcharge added to the winning bid at an auction is a common practice. This fee, calculated as a percentage of the final hammer price, is paid by the purchaser in addition to the bid amount. For example, if an item sells for $1,000 and the associated charge is 20%, the total amount due from the buyer would be $1,200.
This additional charge serves several purposes for the auction house or seller. It can offset the costs of conducting the auction, including marketing, catalog production, staffing, and venue rental. Furthermore, it can sometimes allow the auction house to offer lower commission rates to consignors, attracting more valuable items for sale. Its prevalence has increased over time, becoming a standard practice in many auction environments, providing a predictable revenue stream.