Claims that oil deposits and other extractive resources are “exhaustible” often conflate physical exhaustion (total depletion of the physical stock of a resource) with economic exhaustion (loss of the expected profitability required to induce resource owners to continue extracting and marketing the resource). Yet that distinction is crucial, because when private-property rights are unencumbered, entrepreneurs usually have several strategies available for maintaining the economic value of their firms while they continue to operate them.