In a recent influential paper Coate et al. (2021) have criticized the sequential product-level approach to market definition in merger review. They argue that a simultaneous market-level approach to critical loss is more appropriate than a product-level critical loss analysis, because under certain plausible demand scenarios (nonlinear demand functions) the latter could yield the wrong answer on market definition—i.e., excessively broad or narrow markets. We extend their analysis by showing that a sequential product-level approach actually leads to an excessively narrow market definition when the typical nonlinear demand functions used in merger analysis are employed.

中文翻译：

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关于使用顺序产品级 SSNIP 方法识别相关反垄断市场的风险‡

在最近的一篇有影响力的论文 Coate 等人。（2021）批评了合并审查中市场定义的顺序产品级方法。他们认为，同时对关键损失进行市场层面的方法比产品层面的关键损失分析更合适，因为在某些合理的需求情景（非线性需求函数）下，后者可能会在市场定义上产生错误的答案——即过于宽泛或狭窄的市场。我们扩展了他们的分析，表明当使用合并分析中使用的典型非线性需求函数时，顺序产品级方法实际上会导致市场定义过于狭窄。