Definition
The difference between the highest price a buyer is willing to pay for an asset (the bid) and the lowest price a seller is willing to accept (the ask); a narrower spread generally signals a more liquid, actively traded market, while a wider spread signals thinner liquidity.
In Panel Profits
In the comic secondary market, the bid-ask spread is the gap between the highest offer a buyer has posted for a specific certified issue/grade and the lowest ask a seller has listed for the same issue/grade. Panel Profits uses observed bid-ask spread width, alongside auction and sale-clearing data, as a direct liquidity signal: tight spreads on a given grade tier indicate active, efficient price discovery, while wide or absent spreads indicate a thin, illiquid market for that specific certified tier.
Comic-market example
If the highest standing bid for a CGC 9.4 copy of an issue is $2,800 and the lowest active ask is $3,200, the bid-ask spread for that grade tier is $400.
Calculation
Bid-Ask Spread = Lowest Posted Ask − Highest Posted Bid
Common mistakes
Do not treat a single outlier ask (e.g., an unrealistically high 'aspirational' listing) as representative of the true ask side of the spread without checking for comparable recent activity.