In nonrenewable resource industries, the existence of a markup of price over marginal market cost may reflect the existence of an implicit user cost for the resource rather than market power. We show that valid estimates of market power can be obtained by the joint estimation of a restricted...

An empirical test of the theory of exhaustible resources requires an estimate of the time path of the shadow price of the unextracted resource that generally is not observable because of the prevalence of vertical integration in natural resource industries. In this paper, the authors use duality...