I investigate the effect of competition on quality in the internet service provision industry: I examine both local competition within markets and multimarket contact among firms across markets. This industry offers an ideal setting, as quality is both objective and measurable. I use data from speedtest.net from 2008 to 2014 to estimate a reduced-form model of the effects of local competition and multimarket contact on realized consumer download speeds. I find that increased multimarket contact leads to decreased download speeds, which is consistent with the mutual forbearance hypothesis. I also find that duopolies lead to faster download speeds than do monopolies, but that further increases in the number of competitors decrease speeds.

我研究了竞争对互联网服务提供行业质量的影响：我研究了市场内的本地竞争以及跨市场的公司之间的多市场联系。该行业提供了理想的环境，因为质量既客观又可衡量。我使用 2008 年至 2014 年 speedtest.net 的数据来估计本地竞争和多市场联系对实际消费者下载速度影响的简化模型。我发现多市场接触的增加会导致下载速度下降，这与相互宽容的假设是一致的。我还发现双寡头比垄断带来更快的下载速度，但竞争对手数量的进一步增加会降低速度。