The Federal Reserve released its latest quarterly "Z.1 Financial Accounts of the United States" statistical survey (a.k.a. "Flow of Funds") recently, and among the 4 tables it includes on money market mutual funds, the Fourth Quarter 2025 edition shows that Total MMF Assets increased by $416 billion to $8.190 trillion in Q4'25. The Household Sector, by far the largest investor segment with $5.321 trillion, saw the biggest asset increase in Q4, followed by Nonfinancial Corporate Business and Other Financial Business (formerly Funding Corps). The Fed's latest Z.1 numbers, which contain one of the few looks at money fund investor segments available, also showed noticeable increases for the Mutual Funds and Rest of the World categories in Q4 2025. (Note: Thank you to those who attended and supported our Bond Fund Symposium this week in Boston! Attendees and Crane Data subscribers may access the conference materials via our Bond Fund Symposium 2026 Download Center.)
Households, Nonfinancial Corporate Business, Other Financial Business, Mutual Funds, Rest of the World, Private Pension Funds, Nonfinancial Noncorporate Business, Exchange-traded funds, State & Local Governments and State & Local Govt Retirement categories saw asset increases in Q4, while Property-Casualty Insurance and Life Insurance Companies saw asset decreases last quarter. Over the past 12 months, the Household Sector, Nonfinancial Corporate Business and Other Financial Business categories showed the biggest asset increases.
The Fed's "Table L.206," "Money Market Mutual Fund Shares," shows that total assets increased by $416 billion, or 5.4%, in the fourth quarter to $8.190 trillion. The largest segment, the Household sector, totals $5.321 trillion, or 65.0% of assets. The Household Sector increased by $283 billion, or 5.6%, in the quarter. Over the past 12 months through Dec. 31, 2025, Household assets were up $611 billion, or 13.0%.
Nonfinancial Corporate Businesses, the second-largest segment according to the Fed's data series, held $1.088 trillion, or 13.3% of the total. Assets here increased by $59 billion in the quarter, or 5.8%, and they've increased by $126 billion, or 13.0%, over the past year. Other Financial Business was the third-largest investor segment with $589 billion, or 7.2% of money fund shares. This category rose $48 billion, or 8.9%, in the latest quarter. Other Financial Business, which we believe includes Securities Lending, has increased by $71 billion, or 13.7%, over the previous 12 months.
The Mutual Funds category was the fourth-largest investor segment with $235 billion, or 2.9%, while the fifth-largest segment, Private Pension Funds, held $231 billion (2.8%), and the sixth-largest category, Rest of the World, held $220 billion (2.7%). Nonfinancial Noncorporate Business held $146 billion (1.8%), Life Insurance Companies held $113 billion (1.4%), State & Local Governments held $93 billion (1.1%), Property-Casualty Insurance held $64 billion (0.8%), Exchange-traded Funds held $55 billion (0.7%), and State & Local Govt Retirement held $37 billion (0.5%) according to the Fed's Z.1 breakout.
The Fed's "Flow of Funds" Table L.121 shows "Money Market Mutual Funds" largely invested in "Security Repurchase Agreements" with $2.994 trillion, or 36.6%, and "Debt Securities," or Credit Market Instruments, with $5.021 trillion, or 61.3% of the total. Debt securities include: Open market paper ($319 billion, or 3.9%; we assume this is CP), Treasury securities ($3.518 trillion, or 43.0%), Agency and GSE-backed securities ($1.013 trillion, or 12.4%), Municipal securities ($155 billion, or 1.9%) and Corporate and foreign bonds ($16 billion, or 0.2%).
Another large MMF position in the Fed's series includes `Time and savings deposits ($252 billion, or 3.1%). Money funds also hold minor positions in Miscellaneous assets ($-77 billion, or -0.9%) and Foreign deposits ($0.0 billion). Note: The Fed also lists "Variable Annuity Money Funds," which currently total $50 billion.
During Q4, Debt Securities were up $324 billion. This subtotal included: Open Market Paper (up $5 billion), Treasury Securities (up $285 billion), Agency- and GSE-backed Securities (up $14 billion), Corporate & Foreign Bonds (up $4 billion) and Municipal Securities (up $15 billion). In the fourth quarter of 2025, Security Repurchase Agreements were up $222 billion, Foreign Deposits were unchanged, Time & Savings Deposits were down $10 billion, and Miscellaneous Assets were down $120 billion.
Over the 12 months through 12/31/25, Debt Securities were up $695 billion, which included Open Market Paper (up $20B), Treasury Securities (up $523B), Agencies (up $127B), Municipal Securities (up $17B), and Corporate and Foreign Bonds (up $9B). Foreign Deposits fell $4B and Time and Savings Deposits decreased $12B. Securities Repurchase Agreements were up $374B over the year, while Miscellaneous Assets fell $106B.
The L.121 table shows `Stable NAV money market funds with $7,831 billion, or 95.6% of the total (up $424B or 5.7% in Q4 and up $926B or 13.4% over 1-year), and Floating NAV money market funds with $359 billion, or 4.4% (down $8B or -2.1% in Q4 and up $21B or 6.2% over 1-year). Government money market funds total $6.690 trillion, or 81.7% (up $388B or 6.1% in Q4 and up $779B or 13.2% over 1-year), `Prime money market funds total $1.343 trillion, or 16.4% (up $14B or 1.0% in Q4 and up $152B or 12.7% over 1-year) and Tax-exempt money market funds $158B, or 1.9% (up $15B or 10.6% in Q4 and up $17B or 11.9% last year).
Note that the Federal Reserve made some changes to its Z.1 tables several years ago. Describing a "Money market funds sector data source change," the report says, "The money market mutual funds (MMF) sector (tables F.121 and L.121) has been revised beginning 2010:Q4 to reflect a change in data source to Securities and Exchange Commission Form NMFP. The level of assets and shares outstanding of the sector have increased due to the inclusion of private placement MMFs in the source data. Changes in the level due to changes in the data source in 2010:Q4 are recorded as other volume changes in the Financial Accounts."
On "Mutual funds sector holdings of money market funds," Z.1 tells us, "The mutual funds sector (tables F.122 and L.122) has been revised beginning 2010:Q4 to reflect holdings of money market funds not previously reported on the tables. In addition, holdings of repurchase agreements, commercial paper, corporate bonds, and miscellaneous assets have been revised. Additional and revised holdings are estimated using data from Morningstar and Investment Company Institute.... The exchange-traded funds sector (tables F.124 and L.124) has been revised beginning 2010:Q4 to reflect holdings of money market funds not previously reported on the tables."
