Every figure in this workspace is a base comparable sale multiplied by a published condition factor, recalculated as comps arrive. Figures are current as of 2026-09-23. This page lists every source, every multiplier, and the limits you should know before relying on a number.
Median of recent comparable sales, weighted for provenance, multiplied by condition, recalculated continuously with history preserved.
For each item, PROVENANCE takes recent sales of the same object — same title and printing points, same card and grade, same print state, same reference and dial — across the sources above. The median of the qualifying sales becomes the base value, so a single outlier auction does not set the number.
Documented factors shift value beyond condition: original box and papers on a watch (roughly +25%), an original jacket on a book (+45%), a documented service history, or an authenticated signature. Each is a dated, auditable event in the ledger rather than a guess.
The base is then multiplied by the condition or grade factor for the category. These factors are published on every category page and shown on each item page, so the arithmetic is never hidden: a PSA 10 card carries roughly 3.4x a PSA 8, a Near Fine book in jacket 1.45x, a full-set watch 1.25x.
Each valuation is stored with its date and the comp set behind it. When new comps arrive the value updates, but history is never overwritten — you can see what the ledger said last month and what changed it.
Each source is public and dated. Comps are drawn from completed sales, never asking prices, and are rechecked as new sales settle. Where a source publishes a methodology of its own, it is linked.
Completed and sold listings only, not asking prices. Filtered to verified sellers and listings with photos matching the stated grade.
ebay.comRealized prices from signature and weekly auctions, including buyer’s premium where Heritage publishes it.
ha.comPopulation counts by grade used to contextualize rarity; not a price source on its own.
psacard.com/popCompleted-sale signals and listing medians per reference, dial, and year. Listings are filtered to dealers with verified track records.
chrono24.comListed prices for matching printing points and jacket state, cross-checked against recent auction realized prices.
abebooks.comHammer plus premium for matching states and impressions. Thin lots are down-weighted in the median.
christies.comRanges below are drawn from the same comp sources over the trailing 24 months of this workspace and are consistent with the longer-run figures each category page publishes. They are observations of this demonstration dataset, not forecasts.
| Category | Trailing 24 months | Longer-run range | Primary sources | As of |
|---|---|---|---|---|
| Rare Books & Manuscripts | +9.2% | 8 to 12% annually for near-fine first editions | AbeBooks, Heritage, eBay | 2026-09-23 |
| Vintage Sports Cards | +14.6% | Mid-teens historically, with high volatility | eBay sold, Heritage, PSA | 2026-09-23 |
| Antiquarian Prints & Works on Paper | +7.1% | 6 to 10% annually for lifetime impressions | Christie’s, eBay, dealers | 2026-09-23 |
| Luxury & Collectible Watches | +11.3% | 9 to 14% annually for steel sports references | Chrono24, auctions, private | 2026-09-23 |
Every valuation or appreciation claim elsewhere on this site \u2014 on the landing page, category pages, and item pages \u2014 follows this same method and links back here.
A ledger-based valuation is an estimate from public comps. It is not a certified appraisal, and there are specific situations where it will be wrong.
This workspace is a demonstration: comps and history are seeded from published market ranges as of 2026-09-23, not live feeds. The method described here is the method the product applies; the numbers are representative. Do not declare them to an insurer or file them with a tax authority.
PROVENANCE is an inventory and record-keeping tool. Nothing on this site is financial, investment, tax, or legal advice, and no figure shown \u2014 tracked value, unrealized gain, appreciation percentage, or comp price \u2014 is a recommendation to buy, sell, or hold any asset. Collectibles are illiquid, volatile, and can lose value; past appreciation does not predict future results. Where a certified appraisal is required, engage a member of a recognized appraisal association. Consult a qualified professional before making financial decisions based on any figure in this workspace.
Questions about the method or the data? Write to concierge@provenance.top.