We consider a mixed duopoly selling to downstream retailers that are engaged in spatial price discrimination. We show that the optimal degree of privatization falls below—often far below—the level that is implied in the absence of the vertical chain. The size of this reduction in privatization reflects the extent to which increasing transport cost (differentiation) increases double marginalization in contested market regions—as opposed to simply reducing demand in uncontested market regions. Moreover, we show that despite higher costs of production, a fully public monopoly upstream can be welfare-superior to the optimal mixed duopoly. This would not be the case in the absence of downstream differentiation.

我们考虑向从事空间价格歧视的下游零售商出售混合双头垄断产品。我们表明，最佳私有化程度低于（通常远远低于）缺乏垂直链所隐含的水平。私有化减少的程度反映了运输成本（差异化）的增加在竞争激烈的市场区域中增加了双重边缘化的程度，与简单地减少无竞争市场区域的需求相反。此外，我们表明，尽管生产成本较高，但上游的完全公共垄断相对于最优混合双头垄断而言可能比福利更高。如果没有下游分化，情况就不会如此。