Demand Spillovers and Market Outcomes in the Mutual Fund Industry
研究发现，当消费者集中购买一家公司的产品时，产品种类多的公司所有产品市场份额都会增加，导致行业集中和产品多样化而非降价，美国零售共同基金市场存在强需求溢出效应。
When consumers concentrate their purchases at a single firm, firms that offer more products than their rivals gain market share for all their products. These spillovers induce firms to offer a greater variety of products rather than lower prices, and a concentrated industry with few large firms can arise if spillovers are strong enough. This article presents a simple model that illustrates this mechanism explicitly. The empirical analysis documents strong demand spillovers in the retail segment of the U.S. mutual fund industry, in which fees are nontrivial, families offer many funds, and the market is quite concentrated. Instead, spillovers are weaker, fees are lower, families offer fewer funds, and the market structure is more fragmented in the institutional segment.