Indeed, credit unions in the $2 million to $50 million asset range are not experiencing the same scenarios, according to Tom Glatt Jr., strategy consultant with Glatt Consulting, a Wilmington, N.C. -based firm. In fact, 49% of all credit unions showed zero to negative membership growth, which is up slightly from 47% in the second quarter, he added.

“It's not that membership hasn't increased. What the trades are reporting is accurate,” Glatt said. “Yes, we are growing, but it's the smaller ones that need to grow. You're ignoring half of the credit union community.”

In his third-quarter 2012 Credit Union Industry HealthScore analysis, Glatt found that credit unions in Peer Group 1, or those with assets less than $2 million, had an average HealthScore membership growth of negative 2.07. Those in Peer Group 2, with assets between $2 million and $10 million, had negative 1.01, while Peer Group 3, credit unions with assets between $10 million and $50 million, came in at positive 0.46.

Calculated quarterly, the HealthScore range is based on a five point scale, with five being the healthiest and zero being the least healthy.

The HealthScore numbers with credit unions in Peer Groups 4, 5 and 6, or those with assets in the $50 million to more than $500 million range, is where the real growth is occurring. Those scores, respectively, are 1.88, 2.94 and 4.59.

What are some of the reasons why the smaller credit unions are not growing their memberships? Glatt said one culprit could be visibility.

“You may have a branch that is locked down because it's not in the community. Some of the smaller credit unions are beholden to a single sponsor,” Glatt said. “They likely didn't have an interest in Bank Transfer Day and [former bank customers] are probably not the people that they're attracting anyway.”

Then there are a fair number of credit unions that could care less about increasing their member bases, Glatt said. Instead, they choose to look at other ways to define their success such as through loan and decent deposit relationships. However, for the long term, that measurement could lead to failure.

“Some credit unions were dying on the vine. Their only choice would be to merge,” Glatt said, adding over the past five quarters, the industry has lost 400 credit unions.

Still, those smaller cooperatives that had miniscule or no membership growth in the third quarter, are not the bane of the industry, Glatt noted. There is always room to thrive.

“Small credit unions can be healthy. We should want small credit unions to be healthy. For those small credit unions that aren't, we should push them to do better–and help them when they falter,” Glatt said.

CUNA Mutual Chief Economist Dave Colby offered a second set of data that showed the 100 fastest growing credit unions accounted for 82% of all the membership growth in the third quarter. On the other end of the spectrum, 3,241 credit unions or 46% reported declines. They make up roughly 15% of the industry's assets.

“There's no doubt that there is a real concentration issue, but it's not just about body count,” Colby said. “What it really comes down to is what members are looking for in terms of products and access channels. Your mom and pop credit unions don't have these. They might not have an online or mobile presence.”

Looking back at Bank Transfer Day, Colby said while the national financial institution switch movement brought in 2.6 million new members over the last year, he would want to see what happened after those share draft accounts were opened.

“If you did 90% of your banking with a bank and then moved all your money over to a share draft at a credit union along with your vehicle loan and mortgage, that doesn't count in membership numbers but it certainly does in building relationships,” Colby said.

Both Glatt and Colby emphasized that while the bigger credit unions are the main drivers of membership growth, some of the big cooperatives have problems of their own, too.

In a recent analysis, Glatt pointed out there is a credit union out there with more than $500 million in assets whose HealthScore is less than the average negative 2.07 for credit unions under $10 million in assets.

“Of course, at that size, such credit unions often have far greater reserves to withstand periods of poor health. Again, my point was only to suggest that health and size are not bipolar. Regardless of your size, you can be healthy,” Glatt said.