In auctions, the seller's commission refers to a percentage of the hammer price (the winning bid) of an auctioned item that will be payed by the seller to the auction house as a commission. Commission rates can vary greatly but are usually between 8% and 20%. For instance, if you auction an artwork whose hammer price is $1,000, the buyer will pay a buyer's premium to the auction house, but you as the seller will also pay a fee. Let's say that the buyer's premium is 20% and the seller's commission is 15%: the buyer will pay $1,200 in total ($1,000 + $200), and you will receive $850 ($1,000 - $150). The difference ($200 + $150) is the remuneration of the auction house. Note that, the seller's commission can be negotiated. If you plan to auction high-end artworks ($10K+), auction houses may be inclined to reduce or cancel this commission to ensure that you'll use their services. And on even higher-priced consignments ($50K+), the auction house may be willing to give the seller part of the buyer's premium. See: Comic art auction houses (comparison table)