Two-part marginal cost pricing equilibria: Existence and efficiency

Two-part tariffs are explored in a general equilibrium model with increasing returns to scale. Two-part marginal cost pricing equilibria are not generally Paretoefficient. The Second Fundamental Theorem of Welfare Economics may also fail. We introduce a notion of consumer surplus as the willingness to pay for access to the increasing returns good. The individuals's hookup charge is set to a fixed fraction of his consumer surplus. If aggregate consumer surplus exceeds the losses of the regulated monopoly, then exact two-part marginal cost pricing equilibria exist. Further, for efficient allocations having positive net surplus, the Second Fundamental Theorem of Welfare Economics holds.