Investors grew nervous about U.S. stock funds in late March, according to the latest statistics from the Investment Company Institute. During the week ended April 3, investors withdrew an estimated $1.83 billion from funds that invest long-term in U.S. equities, the most they have pulled from the funds in a single week this year.

Investors were more comfortable putting money in global stock funds, which took in an estimated $3.08 billion, up 8% from $2.85 billion a week earlier.

Bond funds, however, gave investors the greatest comfort. During the week ended April 3, bond funds attracted $6.44 billion in estimated inflows, an 87% increase from the $3.45 billion they took in the previous week. Of the $6.44 billion, $6.36 billion went to taxable bond funds with the remaining $73 million going to municipal bond funds.

Hybrid funds, which invest in both stocks and fixed income securities, drew a respectable $1.15 billion in estimated inflows for the week.

All told, mutual funds pulled in an estimated $8.84 billion for the week, down modestly from $9.09 billion a week earlier.

The weekly fund flow estimates are derived from data covering more than 95% of industry assets, according to ICI.  The statistics cover long-term mutual funds, those the ICI defines as investing in long-term instruments.