This paper demonstrates that the data from a single market with nonlinear prices are consistent with a large set of underlying structural equations. By restricting the permitted functional form of the structural equations, the nonlinearity of marginal prices can be used to identify the price and shift parameters of a single member from the set. The identification approach must be used with great caution, however, because the true shape of supply and demand functions is often unknown and so the necessary restrictions may be unjustified.

The efficiency and equity effects of unit, yield, property, and windfall profits taxes upon nonrenewable resources are compared. The yield tax is the most efficient, and unit and property taxes are the least efficient of current taxes. If the base price of the windfall profits tax is set close to extraction cost, the windfall profits tax can be even more efficient than the yield tax. All the tax burdens fall primarily upon owners. In fact, with the property and windfall profits taxes, consumers can even be made better off.