How an auction sets the price of a work of art
An estimate, a secret reserve, a hammer price and a premium: four numbers decide what a painting really costs. Here is how they fit together.
Zephil Editorial · November 12, 2026 · 2 min read
When a painting sells for a record sum, the headline number is rarely the whole story. At an auction, the price people read about, and the price the buyer actually pays, are not always the same. Understanding the vocabulary is the first step to reading the art market.
The estimate: a guide, not a promise
Before the sale, the auction house publishes an estimate: a range, such as "between two and three million". It is set by specialists from comparable sales, the artist's track record, the condition of the work and its history. It tells bidders where the house expects the bidding to land. It is an opinion, and works regularly sell below or far above it.
The reserve: the price below which nothing sells
The seller can set a reserve, a confidential minimum. By convention it sits at or below the low estimate. If bidding stops short of it, the work goes unsold, which the trade calls "bought in". Most buyers never learn the figure, but a bought-in lot is a public signal, and it can follow a work around the market for years.
The hammer price and the premium
The auctioneer's gavel falls on the hammer price. That is not what the winner pays. The buyer's premium, a percentage published in the catalogue, is added on top, and it usually rises in tiers with the price. Results are often reported "with fees", and the difference can be substantial. When you read a record, check which of the two figures it quotes.
The hammer price is the bid. The final price is the bid plus the house's fee.
Guarantees and the work done before the sale
Many major lots are guaranteed. The auction house, or a third party, commits in advance to a minimum price, which protects the seller. A third-party guarantor often places an irrevocable bid, which means that a lot can have a buyer before the room has even opened. This reduces risk for sellers, and it also shapes how the evening unfolds.
Why it matters beyond the room
Auction results set public reference points. Galleries, collectors, insurers and museums all use them to value other works by the same artist. That is why a single result can move a whole market, and why houses work so hard on the quality of each evening. For anyone following art as an asset or as culture, the useful habit is simple: read the estimate, the premium and the guarantee before reading the headline.