The HobbyGM 30 card index

88.17

On 2026-11-02: −1.6% on the day and −8.7% over 7 days. Base 100 on 2026-10-16.

Breadth

Of the 30 cards in the index on 2026-11-02, 7 are priced higher than a week before and 19 lower. 16 sold at auction that day (33 sales in all).

By sport and game

Supply

Active eBay listings matching the index cards' searches: 6,343 on 2026-11-02. More copies for sale while prices stay flat can mean prices are about to ease.

The cards

Members since 2026-11-01, ranked by how often each sold at auction in the 28 days before. Prices are each card's reference price.

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How the index is built

Prices are sold auctions. Each day HobbyGM finds eBay US auctions of the candidate cards and records what each one sold for when it ends. Only auctions count: an auction's final price is what the market paid that day, where a fixed-price listing's asking price is only what a seller hoped for. Titles are matched to each card on player, year, set, card number, grader and grade, so a PSA 9 or a refractor never counts as a base PSA 10.

Each card gets a reference price: the median of its last 3 accepted sales, carried forward on days it doesn't sell. Once a card has 3 accepted sales, a sale below 0.4× or above 2.5× its reference price is set aside as a likely mismatch (a wrong grade, a damaged slab, shill bidding). If 3 set-aside sales in a row agree with each other, the market has moved, and the history restarts from them.

Members are the most-traded cards. On the first day of each month, candidates are ranked by how many sold auctions they had in the previous 28 days. A card needs at least 4 sales on 3 different days to qualify. The top 30 make the index, with at most 9 from any one sport or game and 2 per player, so no single market or name dominates it. A current member stays in while it ranks in the top 35, which keeps cards from flickering in and out. The index starts once 10 cards qualify, with 14 days of history.

Equal weight, daily change. Each day's move is the geometric mean of the members' price changes that day (a card that didn't sell counts as unchanged), so a $40,000 card and a $300 card count the same, and one card doubling moves the index by the same amount as another halving pulls it back. Days chain together from 100 on the day before the first members were picked; a monthly change of members doesn't move the level.

Sub-indexes for each sport and game are built the same way from that segment's members, and hold their level on days with fewer than 3 members. Supply is the number of active eBay listings matching each member's search, from eBay's own search totals (estimates, and broader than the exact card).

The index and its members are free to use with a link to this page, and available as JSON at /api/market/hobbygm-30. 2 membership periods so far.