Private sales is the auction-house term for the confidential, off-calendar transaction business that runs alongside the public auction programme. The category covers any sale brokered by the firm that does not pass through the auction room: pieces sold quietly between collectors, pieces moved between estates and dealers, and pieces consigned to the firm specifically for off-market placement. Private sales has grown over the past twenty years from a small adjunct to the auction calendar into a strategic priority for Sotheby's, Christie's, Phillips, and Bonhams, and is now reported separately in the houses' annual results.

The auction-house business model

Auction houses make money in two ways: the seller's commission (charged to the consignor) and the buyer's premium (charged to the winning bidder, on top of the hammer price). Public auction generates both revenue streams on every successful lot. Private sale, in most fee structures, generates only one revenue stream, charged as a single commission against the transaction value, with no buyer's premium added. The per-transaction revenue is therefore lower than for an equivalent public auction sale, but the per-transaction operating cost is also lower (no catalogue, no viewing day, no auction-room infrastructure), and the conversion rate is higher because the sale is brokered rather than auctioned.

The strategic value of private sales for the auction house is also broader than the per-transaction economics. Private sales business builds and maintains relationships with the firm's most important clients, both as buyers and as consignors. A collector who sells a piece privately through Sotheby's is a collector Sotheby's continues to know about and to serve; a collector who buys privately through Christie's is on Christie's private offer list for the next opportunity. The relationship value compounds, and the houses have invested heavily in private sales precisely because the long-term client retention benefit exceeds the per-transaction revenue.

Reported volumes and growth

Sotheby's reported private sales of approximately one and a half billion US dollars across all categories in 2022, of which jewellery and watches accounted for several hundred million. Christie's reported private sales of approximately one billion two hundred million dollars across all categories in the same year. Phillips's private sales business is smaller in absolute terms but has grown at a comparable rate. The combined private sales business across the major houses now meaningfully exceeds the value of public auction in some categories, including high jewellery and important coloured stones.

The growth pattern over the past decade has been consistent. Private sales has expanded faster than public auction in essentially every year, and the houses have responded by hiring additional specialists into dedicated private sales roles, building separate viewing rooms and client-services infrastructure, and treating private sales as a distinct business line rather than an afterthought to the auction calendar.

Specialist roles and client relationships

The auction-house specialist who handles private sales does the same gemmological and market-research work as a public-auction specialist but spends a much larger share of their time on client relationship management. The job involves knowing which collectors are buying what, which estates are likely to liquidate within a given window, which dealers hold inventory that is privately for sale, and which families have inherited pieces that may be quietly available. The information network is built over years of client contact and is the firm's most valuable working asset in the private sales business.

Specialists move between firms, and when they do, the client relationships and the information network move with them. The major auction houses therefore compete aggressively for senior specialists in private sales as well as in public auction, and the personnel turnover at the top of the trade reflects the value of these portable client relationships.

Private sales versus dealer trade

The auction houses' private sales business operates in parallel with the traditional dealer trade, with significant overlap. Many of the same pieces could be sold privately through a dealer or privately through an auction house's private sales division; the choice depends on the specific intermediary's reach, fee structure, and relationship with the buyer or consignor. The auction houses have certain structural advantages (global brand, broad client database, deep specialist roster) and certain disadvantages (higher overhead, slower transaction cycle, less flexibility on commission). The dealer trade has the opposite profile.

For the consignor or buyer choosing between channels, the question is usually which intermediary best knows the relevant counterparty for the specific piece. A dealer who has spent twenty years specialising in Burmese ruby is probably a better intermediary for a fine Burmese ruby than a generalist auction-house specialist who handles ruby alongside emerald and sapphire. The auction houses' private sales business competes with the dealer trade by hiring deeply specialised individuals and by offering global reach the average specialist dealer cannot match.

Provenance and confidentiality

Confidentiality is fundamental to the private sales channel. The consignor's identity, the buyer's identity, and the transaction price are all withheld from the public record by default. The auction house provides written documentation of the sale to both parties, including a description of the piece, its gemmological identification, its provenance, and any laboratory reports or warranties that form part of the agreement. Beyond the parties to the transaction and their advisers, however, the sale leaves no public trace.

The confidentiality is not absolute. The auction house records the transaction in its internal database, where future specialists can reference it for provenance and price-history purposes. If the piece returns to market years later, either at public auction or in another private sale, the house's record of the earlier private sale provides chain-of-title and price-history information that the consignor and buyer at that future date will both rely on.

Market structure implications

The growth of private sales has had a measurable effect on the structure of the high jewellery market. Public auction prices, which used to set the trade-wide reference for value across most of the market, now set the reference for only a portion of the market; the rest is transacted privately at prices that may be higher or lower than concurrent auction comparables. The trade has adapted by treating auction comparables as one input among several when valuing pieces privately, rather than as the definitive input.

The growth has also concentrated the most important transactions among a smaller number of intermediaries with the relationships and the specialist depth to handle them. Top-of-market private sales is now a relationship business between a few hundred individuals globally, with very limited entry for newer firms or specialists who have not built the long-term client networks the channel requires.

In the trade

For working dealers and serious collectors, the auction houses' private sales business is now an everyday part of the market structure. Pieces flow through the channel constantly, and a dealer or designer who is not on the major firms' private offer lists is operating with reduced market visibility. Building and maintaining relationships with the private sales specialists at the major houses is therefore part of the basic working infrastructure of the modern high jewellery trade.

Further reading

• GIA Gems and Gemology — gem market and trade articles
• ICA — coloured stone trade reference
• International Gem Society — auction and private sale reference