More than four dozen state lawmakers have penned a letter to Mastercard and American Express, urging the New York-based credit card companies to support a measure that could make it easier to spot suspicious purchases at gun stores.

Credit card companies track spending based on the type of retailer where a card is used — though they do not track the individual items that are purchased. Each purchase is tagged with what’s called a merchant category code, with the master list set by an international standards body. Some categories are fairly broad, such as those for grocery stores and airlines, while others are quite specific. There are unique codes for tent and awning shops, wig and toupee stores — even separate categories for antique shops, secondhand stores and pawn shops.

But there are no codes just for gun retailers.

A Mastercard reference booklet lumps them into a “miscellaneous” category with magic stores, silk flower shops and bottled and distilled water dealers, or a “durable goods” category that also includes lighting fixtures and grave markers.

“I think people would be shocked to find that out,” said State Sen. Zellnor Myrie, who spearheaded the letter, which was shared exclusively with Gothamist. It asks Mastercard and American Express to support the creation of a new code for gun sellers.

“I think the public would agree that it’s important for us to keep track of these things,” Myrie said.

Financial institutions are already required under federal law to report any suspicious activity to the U.S. government, including when they think someone might be committing tax evasion, money laundering or terrorism. Those mandates were established in 1970, when Congress passed the Bank Secrecy Act, and were further expanded after 9/11 through the Patriot Act.

If credit cards had a code for purchases at gun stores, the same laws would let them flag if someone were spending large amounts of money at one dealer, or traveling to multiple gun retailers in a short amount of time. The legislators say that could ultimately help law enforcement to stop crimes like firearms trafficking, or even to prevent mass shootings.

The legislators’ letter cites a 2018 New York Times investigation, which uncovered eight cases when shooters used credit cards to buy guns and ammunition. The man who opened fire inside the Pulse nightclub in Orlando, for instance, purchased two firearms and thousands of rounds of ammunition with six separate credit cards, according to the Times. He reportedly spent more than $26,000 in less than two weeks and searched online for terms including “Credit card unusual spending” and “Why banks stop your purchases.”

Myrie said a new code would make it easier to target individuals who intend to traffic guns or use them for mass shootings. People buying guns legally with no intent to harm people, he said, would have “absolutely nothing to worry about.”

“This, I think, is simply using every tool that we have to help to stem gun violence,” he said. “And frankly, I’m not sure why anyone would be opposed to this, outside of trying to avoid controversy or the politics.”

I’m not sure why anyone would be opposed to this, outside of trying to avoid controversy or the politics.

State Sen. Zellnor Myrie

Critics argue it’s not that simple.

“I don’t see how it works,” Lawrence Keane, senior vice president of government and public affairs for the National Shooting Sports Foundation, said. “I don’t see why it’s necessary. And the only reason it’s being advanced is for a political gun control agenda.”

Keane noted that a buyer already needs to go through a background check to purchase guns from licensed dealers. He said sellers can also choose not to go through with transactions if they feel uncomfortable.

John Deloca, who owns one of New York City’s few gun shops, the Seneca Sporting Range in Queens, told Gothamist he regularly limits prospective buyers.

“If a guy came in and he wanted to buy two AR-15s, I would say, ‘You could buy one today. That’s it. You want to buy 300 rounds of ammo? You can buy one box today, but that’s it.’” he said. “That’s my rules and regulations.”

But Keane worries a new code for gun sellers would lead to credit card companies interfering with people’s second amendment-protected rights.

“If a retailer wants to have a policy, that’s entirely up to them. I have no problem with that whatsoever,” he said. “They’re in a better position to make that judgment than some computer terminal at some bank or some credit card processor, based on some computer code or algorithm.”

The National Rifle Association said in a statement that a code for gun purchases could be used to create a “de facto firearm registration” to confiscate people’s weapons. Federal law limits the sorts of information about gun ownership the government can collect.

Keane also warned it would be logistically difficult to use a different code for firearm retailers, given that many guns are sold in multipurpose stores, like Walmart or Bass Pro Shops. Supporters of a firearm-specific code point to workarounds for other industries, such as in the case of pharmacies within grocery stores that have their own separate registers.

Igor Volsky with the gun control advocacy group Guns Down America thinks it’s at least worth a try.

“There’s no single solution to end all of gun violence,” he said. “Different actors in our society have to step up and do what they can to save lives. That extends to the president, to members of congress and to private companies.”

New York-based Amalgamated Bank, which calls itself “America’s Socially Responsible Bank,” has been at the forefront of the push to create a new code for firearm retailers. The company is outspoken in its support of regulations to reduce gun violence — a strategy Keane from the National Shooting Sports Foundation argues is about politics, not business.

Amalgamated Bank submitted an application to create a code for firearm retailers in 2021. The bank says major credit card companies opposed that application, along with a later appeal, and both were rejected.

Officials at Amalgamated said the company is trying once again and expects the International Organization for Standardization to vote on its new application early next month. The legislators said they hope Mastercard and American Express will support the proposal this time around.

American Express did not respond to a request for comment. A spokesperson for Mastercard said in an email that the company is looking into how a new code could be implemented, if it is approved.

At an event with the Economic Club of New York in 2019, Mastercard’s then-President and CEO Ajay Banga said he personally opposed the proliferation of guns in America. But he expressed some skepticism about whether a credit card company should try to prevent people from buying firearms.

“When you go to a store and you buy diapers, but it also happens to sell guns, should I stop you? Or rather, would you let me know what you’re buying? Would you want me to know that you’re buying diapers and not guns? Is that what you want as your relationship with your card provider?” Banga wondered. “These are very easy things to toss around, but they’re really deep issues that determine — and I think that require — a fair societal conversation.”

An earlier version of this story misstated the year in which Amalgamated Bank submitted its prior application for a new merchant category code. It submitted the application in 2021.