ICI's latest weekly "Money Market Fund Assets" report shows assets inched lower in the latest week to the $4.5 trillion level. Year-to-date, MMFs are down by $204 billion, or -4.3%, with Institutional MMFs down $143 billion, or -4.4% and Retail MMFs down $61 billion, or -4.2%. Over the past 52 weeks, money fund assets are down $15 billion, or -0.3%, with Retail MMFs falling by $43 billion (-2.9%) and Inst MMFs rising by $28 billion (0.9%). (Month-to-date in May, through 5/11, MMF assets have decreased by $29.8 billion to $4.943 trillion according to Crane's MFI Daily, which tracks a broader universe of funds. In April, MMFs fell by $74.3 billion to $4.974 trillion, according to our MFI XLS monthly.) ICI's weekly release says, "Total money market fund assets decreased by $11.07 billion to $4.50 trillion for the week ended Wednesday, May 11, the Investment Company Institute reported.... Among taxable money market funds, government funds decreased by $7.62 billion and prime funds decreased by $4.23 billion. Tax-exempt money market funds increased by $778 million." ICI's stats show Institutional MMFs falling $16.7 billion and Retail MMFs rising $5.7 billion in the latest week. Total Government MMF assets, including Treasury funds, were $3.997 trillion (88.8% of all money funds), while Total Prime MMFs were $408.5 billion (9.1%). Tax Exempt MMFs totaled $95.2 billion (2.1%). ICI explains, "Assets of retail money market funds increased by $5.66 billion to $1.41 trillion. Among retail funds, government money market fund assets increased by $2.76 billion to $1.13 trillion, prime money market fund assets increased by $1.82 billion to $194.69 billion, and tax-exempt fund assets increased by $1.09 billion to $86.26 billion." Retail assets account for just under a third of total assets, or 31.3%, and Government Retail assets make up 80.0% of all Retail MMFs. They add, "Assets of institutional money market funds decreased by $16.74 billion to $3.09 trillion. Among institutional funds, government money market fund assets decreased by $10.38 billion to $2.87 trillion, prime money market fund assets decreased by $6.05 billion to $213.79 billion, and tax-exempt fund assets decreased by $307 million to $8.96 billion." Institutional assets accounted for 68.7% of all MMF assets, with Government Institutional assets making up 92.8% of all Institutional MMF totals. (Note that ICI's asset totals don't include a number of funds tracked by the SEC and Crane Data, so they're approximately $400 billion lower than Crane's asset series.)