This paper examines the output effect of third-degree price discrimination in symmetrically differentiated oligopoly. We find that when the sellers’ input costs are chosen endogenously by an upstream supplier with market power, as opposed to being fixed exogenously, long-standing qualitative conclusions about the effect of price discrimination on aggregate output can be reversed. In contrast to previous findings (e.g., by Holmes, 1989), more intense competition in the strong market than in the weak market can make it less likely that price discrimination raises aggregate output. For linear demand functions, we establish necessary and sufficient conditions under which the output effect changes sign when input costs are endogenized.

本文考察了对称差异寡头垄断中三级价格歧视的产出效应。我们发现，当卖方的投入成本由具有市场支配力的上游供应商内生选择时，而不是外生固定时，关于价格歧视对总产出影响的长期定性结论可以逆转。与先前的发现（例如，Holmes，1989 年）相反，强市场中的竞争比弱市场中的竞争更激烈，可以降低价格歧视提高总产出的可能性。对于线性需求函数，我们建立了当投入成本内生化时产出效应改变符号的充要条件。