Definition
A cognitive bias in which a decision-maker continues investing in a losing endeavor because of the cumulative resources (money, time, effort) already committed to it, even though those prior costs are irrecoverable and should be irrelevant to a rational forward-looking decision.
In Panel Profits
Holding depreciating speculative variants because of high initial retail purchase price rather than rotating capital into appreciating certified blue-chip grails.
Comic-market example
Refusing to sell a cooling 1990s foil gimmick book bought at the market peak because of its original price tag exemplifies the sunk cost fallacy.
Calculation
Sunk Cost = Irrecoverable Historical Capital (Ignored in Forward Discounted Cash Flow)