BidArch research guide
How Ancient Coin Auctions Work
A clear guide to catalogues, estimates, bidding, buyer fees, provenance and post-sale records in numismatic auctions.
Updated 2026-07-19
Read the catalogue entry
A strong catalogue entry identifies the authority, denomination, mint, date, major legends, type, metal, weight, diameter, references, condition and provenance. Treat omissions as questions to investigate rather than details to assume.
Inspect every available image at full size. Compare centering, surfaces, edge, strike and visible tooling with the written description.
Estimate the total cost
The hammer price is not always the final amount. Buyer premiums, taxes, shipping, insurance, currency conversion and import charges can materially change the total. Read the sale terms before bidding and set a total-cost limit.
An estimate is guidance, not a guarantee of value or final price. Scarcity, provenance, condition and bidder competition can move results in either direction.
Bid with a documented plan
Build a shortlist, record comparable results and decide a maximum before the live sale. Avoid changing that limit under time pressure unless genuinely new information appears.
Confirm payment, shipping and export requirements in advance. Some objects or destinations may require additional documentation.
Preserve the post-sale record
Save the invoice, catalogue description, lot images, sale date, auction house and lot number. This documentation supports future research and provenance even when an auction website changes.
BidArch auction catalogues and archives connect published lots with structured reference information so collectors can research before and after a sale.