Running a numismatic auction house: cataloguing, grading, references and platforms

Seen from a distance, numismatic auctions look like any other sale: consignments, a catalogue, bids, invoices. Up close, they have their own demands. Lots are small, numerous and often very similar. Value depends on details (a die variety, a mint mark, a grade) that must be recorded precisely. Collectors are international, specialised and demanding, and they follow a handful of dedicated platforms.

This article looks at what sets numismatic houses apart and how to organise the back office around it. For an overview of how Selloff supports coin, medal and banknote specialists, see Selloff for numismatics.

Collectors identify coins by their references: RIC for Roman Imperial coinage, Sear for ancient and Byzantine coins, Friedberg for gold coins of the world, the Krause (KM) numbers of the Standard Catalog of World Coins, Pick numbers for banknotes, and many regional and national references. A single lot may cite several.

Selloff lets you maintain your own list of reference catalogues. Each lot carries a reference catalogue, the reference number and the catalogue value as structured fields, so lots can be found by reference. Further references can go in the description or in additional fields.

Counterfeit and altered coins are a real risk, and buyers may ask for an expert opinion or a certificate after the sale. Two situations need tracking:

• lots sent for certification, before or after the sale, which must be followed until they come back;
• buyer extensions, when a buyer asks for time to verify authenticity before accepting the lot.

Selloff tracks lots sent to a certification body with a status (sent, returned as authentic, returned as not authentic) and manages extensions. While a lot is in extension, payment to the consignor is blocked; it is released once the extension is validated. Certificate scans can be attached to the lot under their own scan type. See certificate of authenticity.

Every coin needs sharp obverse and reverse images, taken under consistent lighting and matched to the right lot. With hundreds or thousands of lots per sale, the risk lies less in quality than in mix-ups and gaps.

Selloff imports photos in bulk, attaches them to lots by reference and runs an image check that lists lots with missing images before the catalogue is published. For the printed catalogue, image sizes and positions are set per lot and applied to the InDesign export. See photo import & image checks.

Coins are small and look alike. A permanent internal reference and a barcode label on each envelope or holder, applied at intake, prevent mix-ups from description through to shipping. In Selloff, packaging types define how many barcode and lot number labels to print for each lot, and barcode scanning is used when packing. See lot references & barcode labels.

Coin sales often mix lots with different tax treatments: collectors' coins, modern issues and, in some jurisdictions, investment gold subject to special rules. Buyers come from many countries and pay in several currencies. Set the VAT type per lot and the tax rules by branch and client country, and confirm the treatment with your tax adviser. In Selloff, an invoice can also combine lots sold in different currencies, converted into the invoice currency. See VAT & international tax.

Numismatic collectors are specialists: one collects Swiss cantonal coinage, another Roman aurei, a third French banknotes. Recording these interests and each client's buying history lets you contact the right people when a relevant consignment arrives, rather than mailing the whole list. See segmentation & smart lists.