Product Differentiation, Search Costs, and Competition in the Mutual Fund Industry: A Case Study of S&P 500 Index Funds
通过标普500指数基金案例，研究非投资组合差异化和信息摩擦如何导致基金数量众多和费率差异大，并解释为何90年代末资金流向更昂贵的新基金。
We investigate the role that nonportfolio fund differentiation and information/search frictions play in creating two salient features of the mutual fund industry: the large number of funds and the sizable dispersion in fund fees. In a case study, we find that despite the financial homogeneity of S&P 500 index funds, this sector exhibits the fund proliferation and fee dispersion observed in the broader industry. We show how extra-portfolio mechanisms explain these features. These mechanisms also suggest an explanation for the puzzling late-1990s shift in sector assets to more expensive (and often newly entered) funds: an influx of high-information-cost novice investors.