Definition
The price at which an asset would change hands between a willing buyer and a willing seller, neither being under compulsion to buy or sell and both having reasonable knowledge of relevant facts, is that asset's fair market value.
In Panel Profits
In Panel Profits, Fair Market Value (FMV) for a comic issue and grade is derived strictly from verified, arm's-length secondary market transactions (recorded auction sales, verifiable marketplace sales) for that exact issue and certified grade -- never from cover price, seller asking price alone, or estimates extrapolated from a different grade tier. An issue/grade combination with no verified transaction history is marked 'Unpriced' rather than assigned an inferred or estimated value.
Comic-market example
If a specific issue at a specific certified grade has three independently verified recent sales, its FMV is derived from those transactions -- not from that same issue's FMV at a different grade, and not from a single outlier listing.
Calculation
FMV[issue, grade] = Consensus (e.g. volume-weighted median) of verified arm's-length transaction prices for that exact issue and grade
Common mistakes
Do not infer or interpolate an unpriced grade tier's FMV from an adjacent grade tier's FMV. Do not use asking-price listings (unclosed sales) as FMV inputs.