ICI's latest weekly "Money Market Fund Assets" report shows assets fell again in the latest week to the $4.485 trillion level. Year-to-date, MMFs are down by $220 billion, or -4.7%, with Institutional MMFs down $170 billion, or -5.2% and Retail MMFs down $51 billion, or -3.5%. Over the past 52 weeks, money fund assets are down $56 billion, or -1.2%, with Retail MMFs falling by $25 billion (-1.7%) and Inst MMFs falling by $31 billion (-1.0%). (Month-to-date in May, through 5/18, MMF assets have decreased by $47.6 billion to $4.925 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 $16.23 billion to $4.48 trillion for the week ended Wednesday, May 18, the Investment Company Institute reported.... Among taxable money market funds, government funds decreased by $24.68 billion and prime funds increased by $5.55 billion. Tax-exempt money market funds increased by $2.90 billion." ICI's stats show Institutional MMFs falling $26.4 billion and Retail MMFs rising $10.2 billion in the latest week. Total Government MMF assets, including Treasury funds, were $3.972 trillion (88.6% of all money funds), while Total Prime MMFs were $414.0 billion (9.2%). Tax Exempt MMFs totaled $98.1 billion (2.2%). ICI explains, "Assets of retail money market funds increased by $10.17 billion to $1.42 trillion. Among retail funds, government money market fund assets increased by $4.40 billion to $1.13 trillion, prime money market fund assets increased by $4.08 billion to $198.77 billion, and tax-exempt fund assets increased by $1.69 billion to $87.95 billion." Retail assets account for just under a third of total assets, or 31.6%, and Government Retail assets make up 79.8% of all Retail MMFs. They add, "Assets of institutional money market funds decreased by $26.40 billion to $3.07 trillion. Among institutional funds, government money market fund assets decreased by $29.08 billion to $2.84 trillion, prime money market fund assets increased by $1.47 billion to $215.26 billion, and tax-exempt fund assets increased by $1.21 billion to $10.17 billion." Institutional assets accounted for 68.4% of all MMF assets, with Government Institutional assets making up 92.6% 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.)