The Investment Company Institute's monthly "Trends in Mutual Fund Investing: May 2010" shows that money fund assets declined by $21.4 billion, or 0.7% in May, to $2.837 billion. Year-to-date through May 31, money fund assets have declined by $479.7 billion, or 14.5%. Money fund assets represented 26.5% of the $10.7 trillion in mutual funds overall as of the end of May. ICI writes, "Money market funds had an outflow of $21.61 billion in May, compared with an outflow of $126.54 billion in April. Funds offered primarily to institutions had an outflow of $37.50 billion. Funds offered primarily to individuals had an inflow of $15.89 billion." Liquid assets of stock mutual funds, a proxy for how much "cash" stock investors hold, inched up to 3.6% from a record low 3.5% in April. (Look for an update on ICI's monthly "Portfolio Holdings of Taxable Money Market Funds" tomorrow.) In other news, registrations for Crane's Money Fund Symposium, our conference July 26-28 at The InterContinental Boston, have broken over the 200 level. There are only a handful of discounted hotel rooms remaining. Register soon!