What is the difference between a Buyers Premium and a Seller commission?

The sellers commission is the fee charge to the seller by the auction company for their services. This fee is usually a percentage of the sale price. The buyer premium is the fee added to the auction price to determine the final contact price. The Buyers Premium may be a percentage of the auction price or a flat fee. At closing an amount equal to the Buyer Premium is paid to the auction company for their services. Auction fees are usually contingent upon the amount and quality of services provide.