Competition, Product Proliferation, and Welfare: A Study of the US Smartphone Market
研究寡头竞争是否导致市场产品数量过少或过多，以及竞争变化如何影响产品种类和数量，发现美国智能手机市场产品不足，竞争减少会降低产品种类和数量，可能加剧并购的福利影响。
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.