NRA slams credit card company code to track purchases at US gun shops, claiming it's 'creating a national registry of gun owners'

• Visa, MasterCard, and American Express will categorize the purchase of firearms in US shops.
• Gun control activists support the move, while the NRA is calling it an attempt to create a national database of gun owners.

Visa, MasterCard, and American Express will use a new code for gun shop purchases in US stores in a win for gun control advocates that has angered the NRA.

The merchant category codes are four-digit numbers used to classify businesses, indicating the types of services or goods being sold, according to Investopedia. The merchant code does not affect the gun purchase itself, but would allow for more transparency.

Gun-control activists say the new code will help track large or suspicious weapons purchases, while gun rights advocates argue that the new code is unfair to those buying firearms legally since it tracks the type of merchant — stigmatizing all gun shop purchases — not the actual items purchased, Mint reported.

"The ISO's decision to create a firearm specific code is nothing more than a capitulation to anti-gun politicians and activists bent on eroding the rights of law-abiding Americans one transaction at a time," a spokesman for the National Rifle Association said in a statement Sunday.

"This is not about tracking or prevention or any virtuous motivation — it's about creating a national registry of gun owners," the spokesman continued.

The payment giants' decision follows the approval on Friday of the new merchant code by the International Organization for Standardization, a group of standards bodies from more than 160 countries.

Reuters and other outlets first reported the news.

The new code will apply to all purchases at gun and ammunition stores, though gun sales at other types of retailers won't be captured separately, Bloomberg reported.

Following the news, New York City Comptroller Brad Lander said the move would help financial institutions flag suspicious activity at these stores and help save lives.

Visa, the world's largest payment processor, acknowledged the change in a statement Saturday, and said it would "protect all legal commerce on the Visa network in accordance with our long-standing rules."

MasterCard announced Friday that it would protect customers' privacy while focusing on "how it will be implemented by merchants and their banks as we continue to support lawful purchases on our network," per Reuters.

Meanwhile, American Express also said in a statement that it will meet regulations and work to "prevent illegal activity on our network," according to Bloomberg.