Since the start of the recession in January 2008, the share of liquid deposits in credit unions increased 11.2 percentage points and now stands at its highest level ever at 67.5%.

Share drafts, regular shares and money market accounts make up those deposits, according to CUNA Mutual Group's May Credit Union Trends Report, which tracked data through March.

While the record level helps current cost-of-funds, it also implies significant challenges when rates move higher, said Dave Colby, CUNA Mutual chief economist, in the report. Still, rates aren't expected to move up until at least 2014, he added.

Despite almost continuous declines in deposit yields year-over-year savings growth moved up to 6.2%, the highest level since April 2010, the data showed.

“Historically, members increased savings prior to the start of a recession and we hope the recent trend is not a harbinger of yet another economic cycle,” Colby said. “Given the extremely low yield environment, we are concerned and will closely monitor near-term trends.”

Colby said this is especially true since regular shares (0.288% national average yield) are up 10.2% year-over year.

The five payroll Fridays in March boosted month-only savings growth to 2.5% with a 6.9% month-only increase in share draft balances, according to the data.