Value-weighted index, base 100 at the window start: the sum of the basket's observed values against the prior day's, chained daily, each card's move capped so one outlier can't dominate. Values come from real comparable sales resolved on Slabline card pages. The window deepens automatically as history accumulates. Not investment advice.
Own Joe DiMaggio cards?
Track them against this index — live values, a 0–1000 protection score, and a broker-ready insurance schedule. Free.