The Massachusetts Bankers Association is hoping to win hearts and minds of consumers with a new study out of a New Hampshire-based research firm asserting that credit unions generally  do not earn their public subsidies.

The study, titled “Credit Unions in Massachusetts: Growing, Consolidating and Increasingly Exempt from Regulations,” argues growth in the credit union industry is primarily driven by a handful of large credit unions making aggressive inroads into what was traditionally considered the domain of banks. Moreover, the 10 largest credit unions in the state hold 50 percent of the industry’s assets in Massachusetts, the five largest hold 35 percent, and the largest, Digital Federal Credit Union, holds 20 percent.

“We went into this with eyes wide open, as we’ve seen large credit unions expanding into the business lending space and as they’ve continued to push for more powers here in Massachusetts, we wanted to get someone to take a look at the landscape and get a better sense of how do they meet the mandate to serve people of modest means?” said Dan Forte, president of the Massachusetts Bankers Association. “I think the study reveals some new areas that we hadn’t looked at before and the answer is that they’re not giving back according to their mandate.”

The paper also touched on credit union growth as concentrated at federally chartered credit unions, which are exempt from state Community Reinvestment Act requirements, long a point of concern for the bankers’ group.

Though it seems sometimes that banks and credit unions get along about as well as Yankees and Red Sox fans, the issue is of particular interest to both groups this year, as credit unions push for the power to accept public deposits. Last year, they won approval for interstate branching.

To qualify for a low-income designation by the National Credit Union Administration, a credit union must demonstrate that 50 percent or more of its membership makes 80 percent or less of its area’s median income.

The Cooperative Credit Union Association’s president, Paul Gentile, responded to the MBA’s comments:

“The banks seem to be worried about our growth. We have $33 billion in assets, they have what? $335 billion. We’re 10 percent of the marketplace. If they want to have 100 percent, that’s just not good for consumers. You need competition, we’re a very good competitor, and consumers benefit,” he said. “I’ve seen this all before.”

Brian Gottlob is principal at PolEcon Research in Dover, New Hampshire, the firm that produced the paper. He said he gathered his results largely by looking at publicly available regulatory filings, documenting things like assets growth, return on assets and deposit growth.

“One of my interests is the whole notion of subsidies. We subsidize a lot of things: health care is subsidized, we subsidize energy, homeownership. For me the question is not whether they’re good or bad, but what’s the public benefit? And who’s benefitting and by how much?” he said.

Among Gottlob’s other findings was an increase in the number of low-income designated credit unions, from 11 Massachusetts credit unions with that designation in 2012 to 57 this year, including four of the Bay State’s largest credit unions with more than $1 billion in assets.

The designation is of particular interest to the bankers’ association because credit unions with the low-income designation are able to accept nonmember deposits from any source and receive an exemption from member-business lending limits, among other things.

Credit unions didn’t earn those designations by actually serving greater numbers of low-income members, but by increasing their marketing to college students and young people, who, by default, have lower incomes than the median for a given area, Gottlob said.

The MBA revived one of its perennial concerns about the credit union industry: that the lion’s share of growth is happening at large, “bank-like” credit unions that look very different from the tiny community financial institutions they once were.

“They’re clearly not meeting their mandate to serve low- to moderate-income individuals, so don’t reward them by giving them additional powers and, in the longer term, if they want more power, they should be regulated and taxed and treated as banks are,” Forte said.

But Gentile doubled down on that particular point of criticism.

“We find that college students face some of the most difficult financial challenges in America today and we certainly want to serve them,” he said. “To say that it’s easy to serve college students or that they’re some very profitable segment, is just not the case. They’re a challenging group to serve and we spend a lot of time educating them and consulting with them.”