Beto O’Rourke, the Democratic presidential candidate, on Thursday called on banks and credit card companies to address gun violence by refusing to provide services for some firearms sales.
In a statement, Mr. O’Rourke’s campaign said he wanted the financial institutions to stop providing services for sales of assault-style weapons — or any firearms that are sold without background checks — and to stop doing business with manufacturers that produce assault-style weapons.
“However inadvertent or deliberate, credit card companies and banks profit off of those who terrorize our communities,” Mr. O’Rourke said in an email to voters on Thursday. “And we know that in this moment, no one can sit on the sidelines. Everyone has a responsibility to do their part.”
The statement came on the same day of a concerted effort by business leaders to influence the gun debate. In a letter on Thursday, the heads of 145 companies in the United States — including Twitter, Uber, Levi Strauss, Amalgamated Bank and Sporting Goods — urged Senate leaders to consider an expansion of background checks and stronger “red flag” laws.
Mr. O’Rourke’s plan was informed by a New York Times investigation last year that reviewed police reports, bank records and investigator notes from a decade of mass shootings and found that many of the killers had used credit to stockpile high-powered weapons.
In response to that reporting, some banks and credit card networks said that customers were entitled to privacy and independence, and that it was not the companies’ responsibility to create systems to track gun purchases that would allow them to report suspicious patterns.
Some banks have revised their policies in recent years. Citigroup said in March 2018 that it would work only with clients that agreed to certain restrictions on firearm sales, and Bank of America said in April 2018 that it would stop lending money to gun manufacturers that make military-inspired firearms for civilian use.
Payment systems including PayPal, Square and Apple Pay have rules banning firearm sales using their systems.
Mr. O’Rourke, a former Texas representative in Congress who embarked on an unsuccessful but profile-raising Senate run last year, used to represent his hometown, El Paso, where a mass shooting at a Walmart killed 22 people on Aug. 3.
The next day, nine people were killed in another shooting in Dayton, Ohio.
Mr. O’Rourke had an angry, impassioned response to the violence and spent the week off the campaign trail as many of his competitors traveled to Iowa for the state fair and other party activities. The episode drew new attention to Mr. O’Rourke’s flagging campaign, although he still lags in the national polls. He has made gun control a central issue in his presidential bid.
Some companies have waded into the gun control debate this year. Walmart said this month that it would stop selling ammunition that can be used in military-style rifles, discourage its customers from openly carrying guns in its stores, and call on Congress to increase background checks and consider a ban on assault-style rifles. Other retailers, including Kroger, CVS, Walgreens and the Wegmans grocery chain, have asked customers to refrain from openly carrying guns in their stores.
Mr. O’Rourke released an aggressive plan to combat gun violence last month, shortly after he recast his campaign as less of a traditional travel itinerary and more of a moral crusade against President Trump.
The plan would require universal background checks for gun purchases; create a national gun registry; limit the influence of the National Rifle Association by banning political action committee contributions to members of Congress; and ban assault-style weapons, silencers, bump stocks and high-capacity magazines.
The plan would also institute a national firearm buyback program, which would be mandatory for assault-style weapons, under penalty of fine, and would be voluntary for handguns.