An asset's market value can change as a result of changes in tax treatment; investors' perceptions of risk; taste; or households' expectations of future economic capacity arising from, for example, the introduction of new technology.
An asset has a market value that can change.
As Devine has no living relations, it makes sense for the impoverished old men to cook up a scheme by which Michael will assume the dead fisherman's identity, and the pair will divide the money between themselves.