The Investment Company Institute published a brief entitled, "Retirement Assets Total $38.4 Trillion in Fourth Quarter 2023." It includes data tables showing that money market funds held in retirement accounts jumped to $758 billion (up from $722 billion) in the latest quarter, accounting for 13% of the total $5.919 trillion in money funds. MMFs represent just 6.4% of the total $11.887 trillion of mutual funds in retirement accounts. This release says, "Total US retirement assets were $38.4 trillion as of December 31, 2023, up 7.8 percent from September. Retirement assets accounted for 32 percent of all household financial assets in the United States at the end of December 2023. Assets in individual retirement accounts (IRAs) totaled $13.6 trillion at the end of the fourth quarter of 2023, an increase of 7.9 percent from the end of the third quarter of 2023. Defined contribution (DC) plan assets were $10.6 trillion at the end of the fourth quarter, up 8.5 percent from September 30, 2023. Government defined benefit (DB) plans—including federal, state, and local government plans—held $8.7 trillion in assets as of the end of December 2023, an 8.0 percent increase from the end of September 2023. Private-sector DB plans held $3.2 trillion in assets at the end of the fourth quarter of 2023, and annuity reserves outside of retirement accounts accounted for another $2.4 trillion." The ICI tables also show money funds accounting for $539 billion, or 10%, of the $5.820 trillion in IRA mutual fund assets and $199 billion, or 3%, of the $6.057 trillion in defined contribution plan holdings. (Money funds in 401k plans totaled $133 billion, or 3% of the $4.800 trillion of mutual funds in 401k's.)