Nearly a year ago, Mayor Bill de Blasio proclaimed that a new municipal identification card would help thousands of New Yorkers “lead fuller lives, better lives, lives full of respect and recognition.”

More than 670,000 people have obtained the identification cards since the program began in January. One of the program’s goals is to help many of those people obtain bank accounts.

But some of the biggest banks in the city — including JPMorgan Chase, Bank of America and Citigroup — will not accept the cards as a primary source of identification, even though their federal regulators and some smaller banks have approved their use.

The banks’ reluctance threatens to leave thousands of undocumented immigrants and others on the margins of the financial system. For now, many are stuck with costly alternatives like check cashing services that take out a big chunk of a worker’s pay. Or they carry wads of cash around, potentially jeopardizing their safety.

For years, the nation’s banking giants have said they support efforts to extend basic banking services to the estimated nine million American households that are “unbanked,” with no savings or checking account.

In the case of the New York ID cards, those efforts are bumping up against another issue facing the big banks: protecting accounts from fraud and money laundering. In recent years, banks have had to pay hundreds of millions of dollars in fines to settle investigations that found they had failed to adequately prevent money tainted by terrorism or illegal drugs from flowing through their branches.

Caught in the middle are people like Donaldo C. Espinoza, a construction worker in the Bronx, who was unable to get a bank account with the ID card; and Blanca Perez, a housekeeper in Queens, who could not cash a check at Citibank using the ID she got after seeing a commercial for it on Univision, the Spanish-language TV network.

Last spring, officials from the Federal Reserve, Treasury Department and Office of the Comptroller of the Currency said that banks could use the New York identification cards known as IDNYC to satisfy certain requirements of federal anti-money laundering laws.

Still, their letter did not compel the banks to accept the IDs, ultimately leaving the decision up to the individual financial institutions, which must “assess the risk presented” by each customer.

For the big banks, the regulatory guidance was not enough to ease their concerns about being held liable if fraudulent or suspicious accounts were opened with the cards, according to people briefed on the matter who spoke on the condition of anonymity.

“These are business judgments,” said Michael P. Smith, president of the New York Bankers Association. “It is ultimately the institution that has to pass muster if there were ever a problem.”

Bank of America will accept the card only as a secondary form of photo identification. Citigroup is planning to accept the IDs as a secondary proof of identification starting next year. JPMorgan does not accept the card at all.

A JPMorgan spokesman, noting that 35 percent of the bank’s branches are in low- and moderate-income neighborhoods, said, “We are committed to meeting the needs of communities where we do business.”

Some who advocate the use of the ID cards question whether the refusal to accept them has less to do with security concerns and more to do with protecting the bottom line. Regulations reining in fees have reduced the profits banks can make from low-income customers, putting the city’s immigrants among the least attractive sources of potential customers.

“If New Yorkers who rely on IDNYC were perceived to be highly profitable customers, the big banks would no doubt change their tune,” said Deyanira Del Río, a co-director of New Economy Project, which works with community groups in New York.

The lack of acceptance of the New York ID cards was among several concerns the nonprofit group highlighted in a letter last month to banking regulators. In the letter, 16 advocacy groups take particular umbrage with JPMorgan, the country’s largest bank, for what they say are its failures to serve the credit needs of low-income and minority communities.

The advocacy groups focused on JPMorgan in part because it is the city’s biggest bank.

A spokesman for the bank said that Chase Liquid, a prepaid card, “has helped more than a million people gain access to mainstream banking.”

The municipal ID cards are available to all New Yorkers over the age of 14. While the mayor’s office says it cannot track the exact number of immigrants with the cards, it has seen some encouraging signs. In the Corona Park neighborhood of Queens, for example, about 20 percent of the area’s approximately 150,000 residents have the cards, according to the mayor’s office.

Late Wednesday afternoon, at an unrelated event in Brooklyn, the mayor defended the ID card program, saying the cards were being accepted by many banks, credit unions and other organizations and have “had a big impact on everything else in people’s lives, whether it is going for a lease, going for a library card, getting into their child’s school when they have to show an ID.”

As for the banks that have declined to accept the card, the mayor said: “We’re certainly going to talk to them, and we’re certainly going to help them to understand.” He expressed confidence that the banks’ concerns could be overcome.

“I think we can educate these banks about the fact that it is both an extraordinarily accurate ID, but it’s the right thing to do for New York City.”

The mayor emphasized that the cards were developed with input from the New York City Police Department and said the department had been one of the biggest backers of the program. “They want every New Yorker on the street to have an ID card; it greatly improves the work of the NYPD,” Mr. de Blasio said.

To obtain an IDNYC, city residents must produce a form of photo identification and proof of their address, which the United States Postal Service has to confirm. The cards also feature holographic images, laser engraving and other security features to prevent forgery.

The cards are intended to give New Yorkers broad access around the city, where it is nearly impossible to get into a government or commercial office building without showing some form of government-issued ID.

Since taking office in 2014, Mr. de Blasio has pledged to find ways to narrow the gulf between the city’s richest and poorest residents.

A part of that effort, the mayor has said, is making it easier for all New York City residents to gain access to services provided by the city and its many institutions.

For Mr. Espinoza, the 54-year-old construction worker, the need for a bank account was even more straightforward. He needed a place to put his money that was safer than under a mattress in his Bronx apartment.

He signed up for a card in order to open a bank account. But the employee at the Bank of America branch in Lower Manhattan told him that the bank would not accept the card as a primary form of identification, he said.

“I was confused,” Mr. Espinoza, who is originally from Honduras, recalled in an interview. “They told me at the NY ID office that this would work to open up a bank account.”

In the end, Mr. Espinoza said he had to miss a day of work and spend $70 to renew his Honduran passport, which he used to open an account at the bank.

Not every immigrant, advocates said in interviews, has the documents needed or feels comfortable going to the embassy of their home country to obtain a passport. The IDNYC, which assigns a number to each card, is intended to validate a New Yorker’s identity regardless of their immigration status.

Banks are not required by regulators to ensure that their customers are United States citizens or whether they are living in the country legally. Regulators are primarily concerned that the banks can verify that customers are who they say they are.

With that requirement in mind, the de Blasio administration and the New York Bankers Association contacted the federal banking regulators this year asking for guidance on whether the IDNYC cards could be used as a proof of identity.

In April, the regulators responded with what consumer advocates interpreted as an affirmation of the cards. The cards, the regulators outlined in the letter, could be used as a “means of documentary verification.” But ultimately, the regulators left the decisions up to the banks, writing that a bank “may determine that more information than the ID Card is necessary.”

The city stands firmly behind the security features of the cards, emphasizing, as they mayor did, that a dozen credit unions and smaller banks are willing to accept the cards as primary IDs.

Nisha Agarwal, commissioner of the mayor’s office of immigrant affairs, and Scott M. Stringer, the New York City comptroller, said the city plans to “keep talking” to the banks about the cards.

“We have done the work with the regulators,” Ms. Agarwal said. “If there is something else we can do to be helpful with the banks, we will.”

In a statement released Wednesday, Mr. Stringer said his office would contact every bank “to discuss what steps they are taking to change their policy.”

While acknowledging that the guidance from regulators was far from an “ironclad” endorsement of the cards, Keith Mestrich, the chief executive of Amalgamated Bank, said he considered the city cards as sufficient proof of identity and residency.

Amalgamated still requires potential customers to produce a taxpayer ID number from the I.R.S. or the Social Security Administration, along with the city-issued cards. It has opened about 250 accounts with the IDNYC.

“We think protections that are put in place are just as strong as most state drivers’ licenses,” Mr. Mestrich said. “I don’t know why the big banks won’t take them.”

From the NYTimes