March's rebound in mutual fund assets masks bad news for fund companies: Investors are entrusting them with less of their money.

Assets under management increased in March by 2.6%, to $5.769 trillion, according to the Investment Company Institute, the industry's trade group. That follows a painful February, when assets fell 1.6%.

Limited Time Offer

Save $400 off your subscription. Special offer ends April 30, 2017.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.