Visa, Mastercard and American Express say they will implement a new merchant category code for American gun merchants, meaning firearm store transactions are identified.
The card giants made the move after the International Organisation for Standardisation (ISO) approved the creation of the new code in response to pressure from gun-control activists.
Says Visa: "Following ISO’s decision to establish a new merchant category code, Visa will proceed with next steps, while ensuring we protect all legal commerce on the Visa network in accordance with our long-standing rules."
The code, which advocates argue will help track suspicious weapon purchases, will show where purchases are made but not details on what has been bought.
New York City Mayor Eric Adams says: "When you buy an airline ticket or pay for your groceries, your credit card company has a special code for those retailers. It's just common sense that we have the same policies in place for gun and ammunition stores."
However, National Rifle Association. spokesman Lars Dalseide says the code unfairly targets law-abiding gun owners.
Says Dalseide: "The 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."