Frequently asked questions
- What is a price index, exactly?
- A single number that tracks the price performance of a defined basket of items over time — the same construction as a stock index. Each of our indexes holds a fixed basket of 25 cards, weighted by real dollar turnover with a 10% cap, and starts at a level of 1000. If the index reads 1050, that basket's market price is up 5% since inception. The full construction is in the methodology.
- How often does the data update?
- Daily. Prices are snapshotted every morning (with an afternoon catch-up pass for anything the morning missed) and index levels are recomputed immediately after. The site shows its data as-of date in the footer of every page — currently Jul 7, 2026.
- Where do the prices come from?
- From PriceCharting, which aggregates completed marketplace sales into per-card market prices across grades. We snapshot their data daily and never mix sold prices with asking prices.
- What does "PSA 10" mean?
- PSA is the largest trading-card grading company; 10 ("Gem Mint") is its top grade. A PSA 10 card is professionally authenticated and graded flawless — the most liquid, most price-transparent segment of the collectible card market, which is why our flagship indexes track it.
- Why did a card enter or leave an index?
- Selection is mechanical: at each quarterly rebalance the 25 most valuable eligible cards by turnover rank enter, subject to buffer rules that damp churn. Cards can also be removed between rebalances if their price stops updating for too long. Every change is published on the announcements page with the reason.
- What does "stale" or "partial" mean on a chart?
- If a card's price didn't update on a given day, the index carries its last known price forward and flags the day. When more than 20% of a basket is carried forward, the day's level is recorded with status "partial". Flagged days are marked on the charts — we disclose them rather than smoothing them away.
- How does this site make money?
- Some outbound links (the "shop" links next to constituents) are affiliate links — if you buy through them we may earn a commission at no extra cost to you. That's it: no paywall on the indexes, no selling of your data. Affiliate links are marked and disclosed on every page footer and in the full disclosure.
- Is this investment advice?
- No. The indexes and every chart on this site are information about market prices, not a recommendation to buy, sell, or hold anything. Collectibles are volatile and illiquid. See the disclaimer.
- Can I buy the cards in an index?
- Yes — each index page has a "shop this basket" view listing every constituent with a marketplace search link. See, for example, the Pokemon 25 PSA 10 basket.
- How do I get in touch?
- Email altassetindex@gmail.com — corrections, data questions, and methodology critiques are all welcome.