This paper studies (1 ) whether, from a welfare point of view, oligopolistic competition leads to too few or too many products in a market, and (2 ) how a change in competition affects the number and the composition of product offerings. We address these two questions in the context of the US smartphone market. Our findings show that this market contains too few products and that a reduction in competition decreases both the number and variety of products. These results suggest that product choice adjustment may exacerbate the welfare effect of a merger. (JEL D43, G34, K21, L13, L41, L63)

中文翻译：

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竞争、产品扩散和福利：美国智能手机市场研究

本文研究 (1) 从福利的角度来看，寡头垄断竞争是否会导致市场中的产品太少或太多，以及 (2) 竞争的变化如何影响产品供应的数量和组成。我们在美国智能手机市场的背景下解决这两个问题。我们的研究结果表明，这个市场包含的产品太少，竞争的减少会减少产品的数量和种类。这些结果表明，产品选择调整可能会加剧合并的福利效应。（JEL D43、G34、K21、L13、L41、L63）