Stats Active, passive and flows Index fund growth

Index funds hold 53.4% of fund money, 19% of the market

19% of US market cap

The figure that matters for any argument about passive investing distorting prices. Source: Investment Company Institute Fact Book 2026, year end 2025.

Index funds buy the market in the proportions it already has and charge very little. They hold 53.4% of US long term fund assets and about 19% of the whole stock market. Both are correct, and they differ only in the denominator.

53.4%Share of fund assets
about 19%Share of the US market
$20.82tnIndex fund assets
December 2023Crossover date

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