Sell-through rate
Sell-through rate
The headline percentage by which auction-sale health is judged
Sell-through rate is the percentage of lots offered at auction that find buyers, calculated as lots sold divided by lots offered, multiplied by one hundred. It is the single most-cited metric in post-sale reporting from Sotheby's, Christie's, Phillips, Bonhams, and the regional jewellery houses, and the figure most often used by the trade to judge whether a sale was strong, soft, or actively troubled. Sell-through rate is read alongside total hammer, average lot value, and the buy-in (BI) rate to form a complete picture of how a session performed.
How it is calculated
The arithmetic is straightforward: a sale offering 200 lots in which 170 sell records a sell-through rate of 85 per cent. The denominator is the number of lots actually offered from the rostrum or accepted online bids, not the catalogue total — withdrawn lots are excluded. Lots sold include those bought by reserve guarantors and irrevocable bidders unless the houses report those separately, which only the largest evening sales typically do. The complementary figure, the buy-in rate, is one hundred per cent minus the sell-through rate.
Reading the number
Within the international jewellery and gemstone market, sell-through rates above 85 per cent are read as strong, 70 to 85 per cent as healthy, 50 to 70 per cent as soft, and below 50 per cent as a session in trouble. A 'white-glove' sale, in which every offered lot finds a buyer, is reported with that label and is taken as a marker of disciplined estimating, well-judged reserves, and sustained demand for the catalogue's price band. White-glove sessions are not unusual in the small, tightly curated single-owner sales that Sotheby's and Christie's run for major collections; they are rare in larger mixed-vendor jewellery sessions.
Low sell-through rates almost always reflect estimate or reserve calibration rather than absent demand. A sale offering one hundred jewellery lots at estimates twenty per cent above current market may sell sixty of them; the same lots at correctly calibrated estimates would clear ninety. Specialists therefore read sell-through alongside the percentage of sold lots that hammered above the high estimate — strong sell-through with low above-high indicates correct estimating, while strong sell-through with high above-high suggests reserves left money on the table.
Limitations as a market signal
Sell-through is a session-level metric and conceals lot-level dynamics. A sale can record an 85 per cent sell-through rate while the headline lots — the cover stones, the named provenances — fail to sell, signalling weakness at the top of the market that the aggregate figure obscures. Conversely, a 60 per cent sell-through can be entirely accounted for by twenty soft estimates among middle-market goods while the top lots all sell strongly. Trade press reads the cover-lot result and the by-category sell-through alongside the headline figure for this reason.
Guarantees and irrevocable bids further complicate interpretation. A lot covered by an irrevocable bid is contractually sold before the rostrum opens; including such lots in the sold tally can flatter the headline rate. Sotheby's, Christie's, and Phillips disclose guarantee structures in their published terms but do not always break out which sold lots cleared on guarantee versus open competition.
In the trade
For consignors, sell-through rate is the metric most likely to be quoted by the auction house in pre-sale pitches and the one most worth discounting. A category sell-through rate from the season prior — coloured stones at Christie's New York, signed jewellery at Sotheby's Geneva — is a more honest indicator of expected outcome than aggregate sale figures. For collectors and dealers, the watchful read is the by-lot pattern: strong sell-through driven by middle-market goods is a different market signal than strong sell-through driven by top-of-catalogue results, and the published rate alone does not distinguish between them.