The cask itself
Distillery, cask type and size all shape what a cask is worth. A first-fill sherry butt from a sought-after distillery sits in a very different market to a refill hogshead from a widely available one.
How the cask has been used matters as much as what is in it. First-fill, second-fill and refill casks mature spirit differently, and the wood is part of what a buyer is bidding on.

