Institutional investors remain a major force in global capital markets, although their footprint varies sharply by fund type and geography. The 2026 Investment Company Fact Book reports $88.0 trillion in worldwide regulated open-end fund assets, while the OECD reports $65 trillion managed by global investment funds in 2024. The figures below retain each source’s measurement period and scope.
Contents
- Global institutional investment scale
- US fund assets and institutional ownership
- What institutions own
- Flows, strategies, and market concentration
- ETFs and the changing fund market
- Retirement savings and household channels
- UK assets and stewardship
Global institutional investment scale
The worldwide regulated open-end fund market reached $88.0 trillion in 2026, according to the 2026 Investment Company Fact Book. The United States represented $44.8 trillion of that total, Europe represented $27.9 trillion, Asia-Pacific represented $10.2 trillion, and the rest of the world represented $5.1 trillion. These regional figures describe regulated open-end fund assets and should not be treated as a complete measure of every institutional asset class.
The OECD’s Institutional Investor Engagement and Stewardship report measured a different universe in 2024. Global investment funds, including open-end and exchange-traded funds, managed $65 trillion, up 76% from $37 trillion in 2015. The largest 20 asset managers increased assets under management from $30 trillion in 2015 to $56 trillion in 2024, an 84% increase. Those 20 managers accounted for 38% of the assets of all financial institutions in 2024, compared with 32% in 2015.
The OECD also found a strong cross-border pattern. In 76% of OECD, G20, and FSB economies, domestic institutional investors owned a smaller equity share than non-domestic institutional investors in 2024. In almost 80% of those economies, domestic institutional investor ownership was smaller than non-domestic ownership. The comparison indicates that institutional ownership is often shaped by international capital as well as by domestic pension, insurance, and fund markets.
US fund assets and institutional ownership
US-registered investment companies held $45.1 trillion in total net assets at year-end 2025. Mutual funds accounted for $31.4 trillion, exchange-traded funds for $13.4 trillion, traditional closed-end funds for $257 billion, and unit investment trusts for $103 billion. The US mutual fund industry remained the largest in the world on the Fact Book’s measure, with $31.4 trillion in total net assets at year-end 2025.
Institutional investors held $3.9 trillion, or 13%, of mutual fund net assets at year-end 2025. Their holdings included $2.4 trillion in long-term mutual funds and $5.3 trillion in money market funds. The latter figure is larger than the institutional share of total mutual fund net assets because the categories describe different slices of the fund market and should not be added together.
Retail investors held 87% of mutual fund total net assets and 94% of long-term mutual fund net assets at year-end 2025. Institutional investors held 62% of their mutual fund assets in money market funds. Long-term mutual funds had $23.6 trillion in total net assets, while money market funds had $7.7 trillion.
| US fund measure | Amount or share | Measurement date |
|---|---|---|
| US-registered investment company assets | $45.1 trillion | Year-end 2025 |
| Mutual fund net assets | $31.4 trillion | Year-end 2025 |
| Institutional share of mutual fund assets | $3.9 trillion (13%) | Year-end 2025 |
| Long-term mutual fund assets | $23.6 trillion | Year-end 2025 |
| Money market fund assets | $7.7 trillion | Year-end 2025 |
The Fact Book also reports that US-registered investment companies held 33% of US corporate equity at year-end 2025. They held 24% of US and foreign corporate bonds, 19% of US Treasury and government agency securities, 29% of US municipal securities, and 25% of commercial paper. These ownership statistics show the breadth of investment-company exposure across equity, credit, government, municipal, and short-term markets.
What institutions own
Fund composition helps explain why institutional investors can have an outsized effect in some markets even when they hold a minority of aggregate mutual fund assets. Equity funds made up 52% of US mutual fund net assets at year-end 2025. Money market funds made up 25%, bond funds 18%, and hybrid funds 6%.
Households held $22.1 trillion in long-term mutual funds and $5.3 trillion in money market funds at year-end 2025. The Fact Book also reports that households held $1.5 trillion in institutional-investor-style long-term mutual funds; that statistic is marked with a question mark in the supplied source material and should therefore be treated cautiously rather than as independently verified.
Flows moved in different directions during 2025. Mutual funds experienced $552 billion of total net outflows. Long-term mutual funds experienced $1.2 trillion of net outflows, while money market funds received $672 billion of net inflows. The difference between long-term and money market flows is an important indicator of how investors allocated capital within the mutual fund structure during that year.
The market also remained competitive. There were 772 fund sponsors competing in the US market at year-end 2025. From year-end 2015 through year-end 2025, 408 sponsors entered the market and 515 left it, producing a net decline of 107 sponsors. Entry and exit therefore coexisted with a large overall sponsor base.
Flows, strategies, and market concentration
The OECD recorded $26.7 trillion in assets under management using index investment strategies in 2024. Non-index managed investment funds totaled $38.3 trillion. Index strategies devoted almost 80% of their assets to equity, whereas non-index funds devoted almost 40% to equity. The strategy split therefore coincided with a different asset-allocation profile, not merely a different management process.
Domicile mattered within the OECD comparison. In Luxembourg, 88% of funds were non-index funds in 2024. In Ireland, 40% were non-index funds. US-domiciled investment funds managed $30.5 trillion in 2024 and were 53% index and 47% non-index.
Sustainability-related mandates represented another measurable segment. Funds with sustainability objectives or criteria had $3.4 trillion in assets in 2024. The OECD also reported that stewardship codes had been introduced in at least 19 jurisdictions by 2025. These figures cover stated objectives and policy frameworks; they do not establish that all assets under those mandates had identical investment practices.
The concentration data is equally important. The largest 20 asset managers’ $56 trillion in 2024 assets represented 38% of the AUM of all financial institutions, up from 32% in 2015. For readers assessing institutional influence, this points to a market where ownership is distributed across many vehicles but increasingly concentrated among the largest managers.
ETFs and the changing fund market
The US ETF market had 4,495 funds and $13.4 trillion in total net assets at year-end 2025. US ETFs accounted for 70% of the $19.2 trillion in ETF net assets worldwide at that date. Large-cap domestic equity ETFs held $5.0 trillion and represented 38% of ETF net assets.
The Fact Book reports that US-registered investment companies represented 30% of assets managed by investment companies in the United States at year-end 2025. This measure is distinct from the 45.1 trillion in total net assets held by US-registered investment companies, because it compares those assets with the broader investment-company asset universe described by the source.
ETF scale also provides context for institutional portfolio construction. The US market combined $13.4 trillion in ETFs with $31.4 trillion in mutual funds at year-end 2025, while the global ETF total was $19.2 trillion. These are reported asset totals, not a claim that ETF and mutual fund assets represent separate ultimate owners; the same investor may hold both structures.
Retirement savings and household channels
US households had $49.1 trillion earmarked for retirement at year-end 2025, and 74% of households held tax-advantaged retirement savings. Defined-contribution plans and individual retirement accounts invested $14.7 trillion in mutual funds. That retirement mutual fund total represented 47% of all mutual fund assets.
Defined-contribution plans held $7.3 trillion in mutual fund assets and IRAs held $7.4 trillion at year-end 2025. Mutual funds accounted for 52% of defined-contribution plan assets and 39% of IRA assets. In addition, 58% of equity, hybrid, and bond mutual fund assets were held in defined-contribution plans and IRAs. Another $1.4 trillion in long-term variable-annuity mutual funds outside retirement accounts represented 6% of long-term mutual fund assets.
The household channel was broad. A total of 76.0 million US households, or 56.4% of US households, owned US-registered funds at year-end 2025. The number of individuals owning US-registered funds was 128.7 million. Among mutual fund-owning households, median mutual fund assets were $125,000 and the median number of mutual funds owned was three.
More than 60% of mutual fund-owning US households had annual incomes below $150,000 in 2025. Fifty-two percent were headed by individuals aged 35 to 64. Baby Boom households represented 34%, Generation X households 28%, and Millennial households 26% of mutual fund-owning households. The median household income was $125,000 and median household financial assets were $370,400.
Education saving was another measurable household objective. Thirteen percent of mutual fund-owning households cited education as a financial goal, and 15% had 529 plans in 2025. Section 529 savings plan assets reached $576.7 billion at year-end 2025, up 15.2% from year-end 2024. There were 16.9 million 529 savings plan accounts, with an average account size of about $34,200.
UK assets and stewardship
The Investment Association reported that the UK investment management industry reached £10.0 trillion in assets under management in 2024, up 10% year over year. UK funds under management rose 5% to £1.49 trillion. Retail investors accounted for 28% of UK AUM, while pension funds accounted for 27%.
The UK figures use pounds sterling and a national industry scope, so they should not be directly combined with the US dollar totals above. They nevertheless illustrate the importance of institutional channels: pension funds alone represented more than one-quarter of UK AUM in the Investment Association’s 2024 measure.
The OECD also reported that Norway’s Sovereign Wealth Fund held meaningful equity stakes in approximately 70 markets outside Norway in 2024. Together with the cross-border ownership findings, this highlights how sovereign wealth funds, pensions, and large asset managers can transmit investment decisions across national markets.