How HobbyCardIndex Calculates Card Prices
HobbyCardIndex publishes real-time price data for over 7 million sports and trading cards, built from real sold prices on hundreds of thousands of cards, eBay sold listings, and publicly available grading-service population reports. All prices are updated daily and cited to source.
Our Data Sources
Every number on HobbyCardIndex traces back to a named source. We do not blend sources into a single synthesized price, and we do not publish “predicted” values when real data is absent. Below are the three data feeds that power the platform.
Real Sold-Price Data, Primary Price Source
Current card valuations on HobbyCardIndex are built from real sold prices aggregated across completed sales. This sold-price feed is our single source of record for “what is this card worth right now.” We ingest it nightly via licensed access. Coverage spans more than 7 million cards across sports (baseball, basketball, football, soccer, MMA), Pokémon, Magic: The Gathering, and other trading card games.
Every price surface on the platform-market movers, the category heatmap, the grade-ladder grid, portfolio value calculations, and grading-ROI estimates-flows from this sold-price feed and only from it. Narrowing to a single authoritative feed means that when a price looks wrong, we know exactly where to look.
eBay Browse & Find APIs, Sold-Listing Verification
For historical sales context and recent-comp tracking, HobbyCardIndex pulls sold-listing data via the eBay Browse and Find APIs. We consume completed transactions only-both auction-format and “Buy It Now” sales that have closed-filtered by listing condition where available.
eBay sold data is treated as a historical record and a verification layer, not as a current-pricing input. The two feeds are kept separate in the product: sold-price valuations appear on card-detail pages; eBay comps appear in a dedicated sold-listings surface. We do not blend the two into a single price number. That separation is intentional and permanent.
Grading Service Population Data, PSA, BGS/Beckett, CGC, SGC
Population reports from PSA, BGS/Beckett, CGC, and SGC feed population-weighted price modeling and grading-ROI estimates. A PSA 10 on a card with 12 known examples is worth more than a PSA 10 on a card with 4,200 known examples; pop data is what makes that distinction visible. We pull public pop-report data on a regular refresh cycle and surface it alongside grade-ladder pricing on card-detail pages.
Update Cadence
The pricing feed runs on a nightly refresh cycle, typically completing around 2 AM UTC. Card-level prices are updated within 24 hours of new sold-price data publishing. eBay sold-listing data refreshes continuously during market hours and is aggregated on the same nightly cycle. Historical price snapshots are stored as a time-series dataset (TimescaleDB hypertable), which means every prior nightly value is retained indefinitely-the history behind a price chart is real daily data, not an interpolation.
If a card’s price moves significantly intraday on eBay, the sold-listing surface reflects that immediately; the valuation number updates on the next nightly run.
How to Read Our Price Data
Each card-detail page shows up to seven price columns. Here is what each one means:
| Column | What it represents |
|---|---|
| Loose / Raw / Ungraded | Current market value for the card outside a graded slab. This is the baseline price and the most liquid market for most cards. |
| PSA 10 | Gem Mint grade from PSA (Professional Sports Authenticator). PSA 10 is the highest standard grade and typically commands the largest premium over raw. |
| PSA 9 | Mint grade from PSA. For high-volume modern cards, PSA 9 often represents the most realistic outcome from a typical submission. |
| PSA 8 | Near Mint to Mint from PSA. Useful for vintage cards where PSA 8 is a strong result and commands meaningful value over raw. |
| BGS 9.5 | Pristine grade from Beckett Grading Services. Note: this column is internally labeled BGS 10 for historical reasons, but it stores BGS 9.5 data-Beckett’s BGS 9.5 is the equivalent premium-grade benchmark in most market comparisons. True BGS 10 Pristine is extremely rare and falls back into this column only when BGS 9.5 data is unavailable. |
| CGC 10 | Pristine 10 from CGC (Certified Guaranty Company). CGC is the dominant grading service for Pokémon and MTG, and competitive with PSA/BGS on modern sports. |
| SGC 10 | Pristine 10 from SGC (Sportscard Guaranty). SGC is particularly strong for vintage baseball and commands premium premiums on high-grade pre-war cards. |
| Day-over-Day Change | Difference between today’s price and yesterday’s stored snapshot, expressed in dollars and as a percentage. Positive values are shown in green; negative in red. Powered by the TimescaleDB hypertable described in the Update Cadence section above. |
Not every card has data in every column. If a grade has no data, the cell is left blank rather than filled with a placeholder or estimate. Blank means unknown, not zero.
Our Editorial Standards
HobbyCardIndex maintains a clear line between data (objective: what does the sold-price data report this card is worth today) and analysis (interpretive: what does the trend suggest about the market for this player). Data is published without editorializing. Analysis, where it appears-in market reports, trend pages, and long-form research pieces-is labeled as analysis and attributes the specific data behind each claim.
If a price looks wrong, the right move is to tell us. Email [email protected] with the card, the price you saw, and what you believe is correct. We log corrections by date and card, and corrections are applied on the next nightly run once verified. We do not pull corrections quietly-if a price was materially wrong on a card for more than 24 hours, we note the correction date in the price history.
No partner, advertiser, or grading service has any input into how individual cards are priced or ranked on HobbyCardIndex. The full structural independence commitments are on the independence page.
About the Team
HobbyCardIndex is built and maintained by the HobbyCardIndex Editorial Team-a collective of collectors, data engineers, and market researchers who work across the platform. The team is responsible for catalog accuracy, data-source vetting, methodology documentation, and publishing the long-form market research and guides on the site. Bylines on specific pieces appear where relevant; this page is the collective voice.
The platform is independently owned. Not a grading service, not a marketplace, not a breaker. The About page and the Independence page have more on the ownership structure and what that means in practice.
Contact
Questions about methodology, data corrections, press inquiries, and partnership questions all go to [email protected]. The contact page has the full breakdown by inquiry type. We aim to respond within one business day.
If you’re a journalist verifying a number or a researcher who wants the underlying data behind a chart, ask-we send source data on request, free of charge.
Try the platform
Free tier, no credit card. Search any of the 7 million+ cards in the catalog, build a watchlist, and see the market-intel dashboard. The basic price tools are not gated.
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