Seller's commission is the percentage charged by an auction house to the consignor of a lot, deducted from the hammer price before the consignor receives settlement. In the international jewellery and gemstone market, published commission schedules at Sotheby's, Christie's, Phillips, and Bonhams typically range from 10 per cent for high-value lots up to 25 per cent or more for low-value goods, with negotiated rates and waivers common at the top of the market. Seller's commission is distinct from the buyer's premium, which is added to the hammer price and paid by the purchaser; both fees together comprise the auction house's principal revenue from a sale.

Published rates and negotiation

Major-house schedules generally tier seller's commission by lot value: lower percentages on high-value consignments, higher percentages on smaller lots. A signed jewel estimated at $500,000 to $700,000 might be consigned at 6 to 10 per cent seller's commission, while a $5,000 estate ring would carry 20 to 25 per cent. The schedules are starting points for negotiation rather than fixed prices, and large or strategic consignments routinely settle at materially lower rates — single-owner sales of museum-quality coloured stones have been reported as commission-free or even at negative rates where the house pays an enhancement to secure the consignment.

Beyond the headline rate, consignors negotiate a list of ancillary terms: insurance during the consignment period, photography and cataloguing fees, illustration in the printed catalogue versus online-only, marketing exposure, reserve level, the inclusion or exclusion of guarantee coverage, and the timing of settlement after the sale. The full bundle determines net realisation rather than the commission percentage alone.

What the commission funds

Seller's commission underwrites the cataloguing, photography, condition reporting, gemmological certification (where commissioned), printed and online catalogues, exhibition space, security and transport during pre-sale viewing, marketing across the house's channels, the rostrum operation itself, and post-sale administration. For a fine coloured stone or signed jewel, the laboratory work alone — Gübelin, SSEF, AGL, GIA reports as appropriate — can run several thousand dollars per lot before any other cost is counted. The commission also funds the specialist's time, which on a major consignment can run to many days of relationship management, condition assessment, and curation.

Settlement and timing

Auction-house settlement to consignors typically occurs 35 days after the sale, contingent on the buyer paying. The consignor receives the hammer price minus the agreed seller's commission and any agreed ancillary deductions. Where the buyer fails to pay, the lot is treated as unsold from the consignor's point of view; the house may pursue the buyer for breach but the consignor's settlement is held back. Collateralised lots — those guaranteed by the house or by an irrevocable bid — settle on the agreed timeline regardless of buyer payment status.

In the trade

For consignors of significant jewellery and gemstone material, the seller's commission rate in the published schedule is rarely the rate paid. A serious approach asks the auction-house specialist for a comprehensive net-realisation projection — hammer at low estimate, hammer at mid estimate, hammer at high — net of all fees, in writing. Published schedules are most relevant for smaller estate consignments where negotiating leverage is limited, and for online-only and second-tier sales where rates are firmer. Across consignments, modelling net realisation rather than gross hammer is the discipline that separates informed sellers from those who learn afterwards what the costs actually were.

Further reading

• GIA Gems & Gemology — auction-market practice articles
• ICA — auction-house and consignment commentary
• AGTA — trade terminology reference