Active vs passive mutual funds in the U.S. 2010 and 2019, with a forecast for 2025

While passive funds only constituted 20 percent of the mutual fund market in the the United States in 2010, it is projected that over half of all U.S. mutual funds will be passive by 2025. Active mutual funds are funds of pooled money that is invested by a fund manager, who actively researches new investment opportunities and amends the fund's portfolio accordingly. This contrasts to passive funds, where the fund's portfolio is (usually) determined by an external stock market index such as the Dow Jones Industrial Average or the FTSE 100.

尽管在2010年，被动型基金仅占美国共同基金市场的20%，但预计到2025年，美国所有共同基金中超过一半将转变为被动型。主动型共同基金是由基金经理管理的资金池，基金经理会积极研究新的投资机会并据此调整基金的投资组合。这与被动型基金形成鲜明对比，在被动型基金中，基金的投资组合（通常）由外部股票市场指数如道琼斯工业平均指数或富时100指数所决定。