Mutual funds hold 32% of the U.S. equity market and comprise 58% of retirement savings, yet retail investors consistently make poor choices when selecting funds. Theory suggests poor choices are partially due to fund managers creating unnecessarily complex disclosures and fee structures to keep investors uninformed and obfuscate poor performance. An empirical challenge in investigating this “strategic obfuscation” theory is isolating manipulated complexity from complexity arising from inherent differences across funds. We examine obfuscation among S&P 500 index funds, which have largely the same regulations, risks, and gross returns but charge widely different fees. Using bespoke measures of complexity designed for mutual funds, we find evidence consistent with funds attempting to obfuscate high fees. This study improves our understanding of why investors make poor mutual fund choices and how price dispersion persists among homogeneous index funds. We also discuss insights for mutual fund regulation and academic literature on corporate disclosures.

共同基金持有美国股票市场的 32%，占退休储蓄的 58%，但散户投资者在选择基金时总是做出错误的选择。理论表明，糟糕的选择部分是由于基金经理创建了不必要的复杂披露和费用结构，以使投资者不知情并掩盖糟糕的表现。研究这种“战略混淆”理论的一个经验挑战是将被操纵的复杂性与基金之间固有差异引起的复杂性隔离开来。我们研究了标准普尔 500 指数基金之间的混淆，这些基金具有大致相同的法规、风险和总回报，但收取的费用却大不相同。使用为共同基金设计的定制复杂性度量，我们发现证据与试图混淆高额费用的基金一致。这项研究提高了我们对投资者为何做出糟糕的共同基金选择以及同质指数基金之间价格分散如何持续的理解。我们还讨论了对共同基金监管的见解和有关公司披露的学术文献。