Mutual funds sold via brokers offer fund portfolios that investors can purchase in one of three classes: A, B or C. These classes are distinguished only by their fee schedules and thus have different net performance results. An analysis of relative class performances for a set of U.S. mutual funds between 1992 and 2008 reveals a striking fact about class B: while classes A and C provide the best performance results at long and short holding periods, respectively, class B is dominated by either class A or C at any holding period. The inferiority yet popularity of class B at first suggests that naïve investors who do not understand the fee schedule of this class are being exploited. However, I propose two hypothetical clienteles which might rationally demand class B shares: one (a) with uncertain holding periods, or one (b) that desires to have long holding periods but is unable to commit to them. I identify whether investors rationally or naïvely purchase class B by examining the flow-fee sensitivity and estimating investor holding periods. My results support the naïve investor explanation.

中文翻译：

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零售金融市场的费用复杂性和投资者错误

通过经纪人出售的共同基金提供基金投资组合，投资者可以购买以下三个类别之一：A、B 或 C。这些类别的区别仅在于其收费表，因此具有不同的净业绩结果。对 1992 年至 2008 年间一组美国共同基金的相对类别表现的分析揭示了一个关于 B 类的惊人事实：虽然 A 类和 C 类分别在长期和短期持有期间提供最佳表现结果，但 B 类主要由任何持有期的 A 类或 C 类。B 类的劣势但受欢迎，首先表明不了解该类收费表的幼稚投资者正在被剥削。但是，我提出了两种可能会合理要求 B 类股票的假设客户：一种 (a) 持有期不确定，或一个 (b) 希望拥有较长的持有期但无法承诺的人。我通过检查流量费敏感性和估计投资者持有期来确定投资者是理性地还是天真地购买 B 类。我的结果支持天真的投资者解释。