From Forbes:

State legislatures, however, are finding ways to pressure banks.  Recently,  California Assemblywoman Sydney Kamlager-Dove (D-Los Angeles) introduced a resolution to urge  “banks that have open demand accounts with the state to evaluate their relationships with gun manufacturers and adopt lending practices that protect citizens before profits.”  The resolution states the California has “demand accounts with six banks that concurrently lend to gun manufacturers, which are Bank of America, Citibank, JPMorgan Chase & Co., Union Bank MUFG, U.S. Bank, and Wells Fargo & Co.”  According to Kamlager-Dove, “California has more gun laws than any other state in the union.”  Hence, instead of proposing new laws, Kamlager-Dove’s resolution “intends to affect the proliferation of guns by urging six nationally chartered banks to curtail their relationships with gun manufacturers. If major banks refuse to extend credit to gun manufacturers, borrowing costs for gun manufacturers would likely increase, which could reduce industry investment in additional capacity or new business lines.” Moreover, “such a result could reduce the proliferation of guns not only in California, but also across state lines.”