More cash flowed out of U.S. mutual funds in March than flowed in.

The funds reporting $6.4 billion in total net asset outflows in March, compared with about $24 billion in net incomes in March 2008, according to Financial Research Corp., Boston.

Domestic stock funds suffered the sharpest drop, swinging to $19 billion in net outflows, from $17 billion in net inflows.

Corporate bond funds bucked the trend. They suffered $778 million in net outflows in March 2008: In March 2009, they attracted $17 billion more in assets than they lost.

International-global stock funds reported $14 billion in net outflows, compared with $165 million in net outflows for March 2008. International-global fixed income funds reported $2.2 billion in net outflows, down from $3.8 billion in net inflows.

The outflows appeared to be related to a shift in investing habits as well as to a flight to safety: The managers of the safest funds of all, money market funds, watched $76 billion in cash flow out in March. In March 2008, the money market fund managers watched $46 billion in cash flow in.