The Complicated Simple Economics of Vertical Mergers
研究上游垄断企业与下游两家伯川德竞争企业之一合并的影响，提出净下游定价压力（NDPP）指标筛选可能损害消费者的合并，模拟发现多数合并不导致涨价，且效果对需求函数形式不稳健。
We model a vertical merger of an upstream monopolist with one of two downstream producers engaged in Bertrand competition. The theoretical model suggests a statistic—the net downstream pricing pressure (NDPP)—that can serve as a screen for which vertical mergers are most likely to result in consumer harm. We simulate the effect of a vertical merger for four different functional forms of demand. In the simulations, relatively few vertical mergers lead to price increases that harm consumers. Of those that do, many would be unprofitable absent efficiencies, and many would be with the smaller of the two downstream firms. Moreover, predicted merger effects are not robust to the assumption about the functional form for demand. In contrast, the NDPP statistic is highly correlated with the change in real output for all functional forms.