The last time certificate of deposit balances at credit unions peaked was in March 2009.

The savings instruments are now nearly $38 billion or 16% off that crest established four years ago, according to CUNA Mutual Group's April Credit Union Trends Report, which tracked data through February.

Members continue to prefer liquid deposits with money markets accounts, share drafts and regular shares accounting for 110% of the $53 billion savings gain during the past year, the data showed.

Share drafts (0.28% yield) were up 11.1% since February 2012 while regular shares (0.24% yield) increased 12.3% and MMA (0.35% yield) increased 6.9%. Meanwhile, CDs (0.80%) fell 2.6%.

“As low as rates appear, credit unions must be very vigilant in their rate-setting policy and quick to adjust rates lower if necessary,” said Dave Colby, CUNA Mutual chief economist.

“This is due to weak loan growth and extremely low investment yields. The only sustainable way for credit unions to pay members higher returns is to grow loans in portfolio,” Colby added.

The credit union industry finished 2012 with annual savings growth of 6.1%, which was just slightly above its long-term rate of expansion, according to the trends report.