The Investment Company Institute's latest weekly "Money Market Fund Assets" report shows MMF assets lower for the second week in a row following an 8-week record-breaking tear. ICI's asset series fell $16.1 billion to $5.870 trillion in the past week, but it has risen $262.5 billion the past 10 weeks. Assets are up by $1.135 trillion, or 24.0%, year-to-date in 2023, with Institutional MMFs up $536 billion, or 17.5% and Retail MMFs up $599 billion, or 35.7%. Over the past 52 weeks, money funds have risen a massive $1.157 trillion, or 24.6%, with Retail MMFs rising by $618 billion (37.3%) and Inst MMFs rising by $539 billion (17.7%). The weekly release says, "Total money market fund assets decreased by $16.09 billion to $5.87 trillion for the week ended Wednesday, December 20, the Investment Company Institute reported. Among taxable money market funds, government funds decreased by $24.02 billion and prime funds increased by $7.66 billion. Tax-exempt money market funds increased by $269 million." ICI's stats show Institutional MMFs falling $26.1 billion but Retail MMFs rising $10.0 billion in the latest week. Total Government MMF assets, including Treasury funds, were $4.794 trillion (81.7% of all money funds), while Total Prime MMFs were $955.3 billion (16.3%). Tax Exempt MMFs totaled $120.8 billion (2.1%). ICI explains, "Assets of retail money market funds increased by $9.96 billion to $2.28 trillion. Among retail funds, government money market fund assets increased by $8.95 billion to $1.48 trillion, prime money market fund assets increased by $897 million to $683.28 billion, and tax-exempt fund assets increased by $110 million to $110.20 billion." Retail assets now account for well over a third of total assets, or 38.8%, and Government Retail assets make up 65.2% of all Retail MMFs. They add, "Assets of institutional money market funds decreased by $26.05 billion to $3.59 trillion. Among institutional funds, government money market fund assets decreased by $32.97 billion to $3.31 trillion, prime money market fund assets increased by $6.77 billion to $271.98 billion, and tax-exempt fund assets increased by $159 million to $10.57 billion." Institutional assets accounted for 61.2% of all MMF assets, with Government Institutional assets making up 92.1% of all Institutional MMF totals. According to Crane Data's separate Money Fund Intelligence Daily series, money fund assets have fallen by $9.3 billion month-to-date in December (through 12/20) to $6.258 trillion after spiking $219.8 billion in November. Assets fell by $31.9 billion in October after rising by $93.9 billion in September, $98.3 billion in August and $34.7 billion in July. Note that ICI's asset totals don't include a number of funds tracked by the SEC and Crane Data, so they're over $400 billion lower than Crane's asset series.