As noted on Christie’s website, a buyer’s premium is the “percentage (%) the buyer pays in addition to the final bid price or hammer price in respect of each Lot purchased.” In other words, the buyer’s premium is a charge added on top of the successful bid amount, and is usually expressed as a percentage of that successful bid amount.
For real estate auctions, the buyer’s premium is generally 5 to 10 percent of the successful bid amount. For personal property, chattel, and antique auctions the buyer’s premium is generally 10 to 15 percent.
For example: A purchaser successfully bids for a house at $100,000. If the auction house handling the sale has a 10 percent buyer’s premium on purchases, the buyer’s premium would amount to $10,000. The final purchase price of the property, with the buyer’s premium, would be $110,000.
It is also important to note that a very small handful of auction houses do not charge a buyer’s premium on purchases; therefore, a high bid amount of $100,000, without a buyer’s premium, would lead to a final purchase price of $100,000. Although, there may not be a buyer’s premium, the seller still pays a commission to the auction company.