The Modern Mutual Fund Family
研究发现，共同基金家族中指数基金的存在能提升主动管理基金的业绩，这种效应与费用水平正相关，暗示道德风险，而内部竞争则激励基金经理努力。
Modern mutual fund families include more than active mutual funds (AMFs). AMFs in families with greater index mutual fund (IMF) presence generate higher category-adjusted gross returns. Performance is positively related to the levels of passive and active fees, suggesting moral hazard. Intrafamily competition from IMFs in the same Morningstar category incentivizes managers to exert effort. Financial resources do not contribute to the performance effect. Cross-trading with IMFs occurs with some positive effect on performance. ETFs have no impact on performance. IMFs reduce flow-performance sensitivity and flow volatility of AMFs in the family. IMFs and ETFs uniquely contribute to expense pressure.