We examine the relative benefits of regulatory commitment and discretion arising from the incompleteness of contracts. Full commitment gives strong incentives for investment, but leaves the regulator unable to bring prices in line with costs or gives the firm large rents. Full discretion on the other hand offers no incentive to invest, but achieves allocative efficiency. We consider a monopoly firm with known demand but unknown costs and show that the elasticity of demand, the cost of investment, the weight on profits and the level of uncertainty are important factors in determining the optimal level of commitment.
