ICI's latest weekly "Money Market Mutual Fund Assets" shows a decrease of $11.34 billion to $3.806 trillion for the week ended April 22. This represents the fifth weekly drop in the past 6 weeks and pushes money fund asset totals into the red year-to-date. While this week's drop was clearly tax-related -- retail assets declined by $16.30 billion to $1.311 trillion (representing 34% of total money fund assets) while institutional assets rose by $4.96 billion to $2.495 trillion -- it's also clear that money fund assets are beginning to face a stiff headwind. Year-to-date, money fund assets have declined by $23.8 billion, or 0.6%. Over the past 6 weeks money funds have lost over $100 billion, or 2.6%. See also the transcript of SEI's earnings and discussion of SIV issues (on the website Seeking Alpha).