A release from the Investment Company Institute tells us that, "Retirement Assets Total $35.4 Trillion in First Quarter 2021." It includes data tables showing that money market funds held in retirement accounts fell to $557 billion (from $574 billion) in total, or 12% of the total $4.497 trillion in money funds. MMFs represent just 4.9% of the total $11.483 trillion of mutual funds in retirement accounts. The release says, "Total US retirement assets were $35.4 trillion as of March 31, 2021, up 1.8 percent from December 31, 2020. Retirement assets accounted for 32 percent of all household financial assets in the United States at the end of March 2021. Assets in individual retirement accounts (IRAs) totaled $12.6 trillion at the end of the first quarter of 2021, an increase of 2.8 percent from the end of the fourth quarter of 2020. Defined contribution (DC) plan assets were $9.9 trillion at the end of the first quarter, up 2.1 percent from December 31, 2020. Government defined benefit (DB) plans -- including federal, state, and local government plans—held $7.1 trillion in assets as of the end of March 2021, a 0.7 percent increase from the end of December 2020. Private-sector DB plans held $3.4 trillion in assets at the end of the first quarter of 2021, and annuity reserves outside of retirement accounts accounted for another $2.5 trillion." The ICI tables also show money funds accounting for $381 billion, or 7%, of the $5.647 trillion in IRA mutual fund assets and $176 billion, or 3%, of the $5.837 trillion in defined contribution plan holdings. (Money funds in 401k plans totaled $119 billion, or 3% of the $4.559 trillion of mutual funds in 401k's.)