"The only way to make these gains work for members and credit unions is to move rapidly to multiple mutually beneficial product relationships," Colby said. "If we don't, next year's credit union's headlines will read 'CUs Rush to Purge Unprofitable Members as Best Members Leave."'

At the end of 2011, 88% of membership gains were generated by credit unions with assets in excess of $1 billion, according to the report.

Colby said not all credit unions participated in last year's growth. Roughly 54% or 3,900 credit unions reported membership declines in 2011. These credit unions hold 27% of industry assets, the data showed.

Meanwhile, January data from CUNA Economics & Statistics showed a net loss of nine credit unions. Colby said that figure is in conflict with the NCUA's Monthly Activity Report, which indicated 22 approved mergers. CUNA's data will undergo semiannual benchmark revisions next month to match it up with final year-end 2011 Call Report data revised from July 2011 to January 2012, he added.

The most current results showed 7,330 credit unions at the end of January with the total institution count down 255 during the past 12 months. A detailed look at NCUA and privately insured credit union data revealed 183 credit unions with assets in excess of $1 billion versus 169 credit unions at the end of 2010. The share of assets for this group is more than 48%, up from 46% in 2010.

On the opposite end of the asset spectrum, 5,005 credit unions or 69% ended 2011 with assets below $50 million. This group held roughly 6.9% of industry assets, which was down from 7.5% at year-end 2010.

"We anticipate regulatory and expense pressures to continue to impact smaller institutions significantly, with overall consolidation rates climbing again in 2012," Colby said.

Regardless of their asset size, credit unions continue to see some signs of life in the lending sector. At almost $586 billion, year-over-year loan growth improved to 1.5%, which was the best showing since late 2009, Colby said. Total loans, however, declined fractionally in January due to usual seasonal factors, according to the report.

For the second consecutive month, total loans, real estate loans and vehicle loans all posted positive annual growth. While unsecured loans and most likely private student loans grew in January, on an annual basis, first mortgages led the way, up $11.2 billion.

Gains in this portfolio segment were followed by $6.2 billion (6.1%) in used vehicles, $2.4 billion (6.4%) in member business loans and $1.5 billion (4.2%) in credit cards.

Colby said taking away from growth were home equity and second mortgages, down $6.0 billion (6.9%) and new vehicle loans down $4.3 billion (6.7%).

"Looking at detailed Call Report data, we see roughly 56% of all credit unions [or 4,087] reported declines in total loans," Colby noted. "These credit unions held 37% of system assets. This is an improvement from year-end 2010 results when 59% of credit unions [54% of system assets] reported loan portfolio erosion."