Demand Spillovers And Market Outcomes In The Mutual Fund Industry
When consumers concentrate their purchases at a single firm, a firm that offers more products than its rivals can gain market share for all its other products, as well. These spillovers induce firms to compete by offering a greater variety of products rather than lower prices, and a natural form of industry concentration with few large firms offering many products can arise if spillovers are strong enough. This paper 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 non-trivial, families offer a large number of funds, and the market is quite concentrated.