On the General Equilibrium Effects of Market Power

Abstract

In an economy in which firms exercise market power in the markets for consumption goods and inputs (labor), we show that a merger to monopoly is Pareto improving when the number of firms is below a threshold. This threshold is larger the larger is the elasticity of labor supply and the smaller is the consumers'preference for goods variety. Consequently, market concentration may have non-monotonic general equilibrium effects on wage mark downs, employment and welfare.