Sufficient conditions are developed for third-degree price discrimination by a monopolist serving all markets to reduce and raise social welfare.  Welfare falls if the demand function in the market whose price is higher with discrimination is at least as convex as that in the other market (at...

The effects of demand shifts on output, price and profits in imperfectly competitive industries with no entry or exit are derived. Four types of demand shift are modelled: additive and multiplicative shifts of the demand and inverse demand functions. Necessary and sufficient conditions for...

This paper presents simple conditions for monopoly third-degree price discrimination to have negative or positive effects on aggregate consumer surplus.  Consumer surplus is often reduced by discrimination, for example when total welfare (consumer surplus and profits) falls.  Surplus increases...

The welfare effects of third-degree price discrimination are analyzed when demand in one market is an additively shifted version of demand in the other market and both markets are served with uniform pricing. Social welfare is lower with discrimination if the slope of demand is log-concave or...

This paper uses convexity arguments to determine the effects of monopolistic third-degree price discrimination on total output and welfare. We focus on benchmark cases, including constant demand elasticities, with constant curvature of inverse demand σ. We show how the effects of price...