We study the impact of tacit collusion on price dispersion in the U.S. airline industry. We find that tacit collusion driven by multimarket contact has a positive effect on prices, but a negative effect on price dispersion. Our empirical results suggest that airfares throughout the price distribution increases, yet the price distribution becomes more compressed since 10th percentile airfares increase by a larger amount than 90th percentile airfares. Moreover, we also find that this pricing phenomenon does not exist if Southwest Airlines is present on the route. Thus, route-level price competition is softened when the same airlines directly compete more frequently, except when Southwest Airlines services that route. As such, our empirical analysis provides evidence that the presence of Southwest Airlines exhibits an anti-collusive effect.

中文翻译：

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西南航空存在的默契勾结和价格分散

我们研究了默契共谋对美国航空业价格分散的影响。我们发现由多市场联系驱动的默契合谋对价格有积极影响，但对价格分散有负面影响。我们的实证结果表明，整个价格分布中的机票价格都在增加，但由于 10% 的机票价格比 90% 的机票增加的幅度更大，因此价格分布变得更加压缩。此外，我们还发现，如果航线上有西南航空公司，则这种定价现象不存在。因此，当同一航空公司更频繁地直接竞争时，航线级别的价格竞争就会减弱，但西南航空公司服务该航线时除外。因此，我们的实证分析提供了证据，证明西南航空公司的存在表现出反串通效应。