American Banker (where, full disclosure, my wife works) has the details:
Bank of America . . . reportedly wants to discourage some gun manufacturers from even having accounts at the bank. Largely neglected by the mainstream press, two particular firearms manufacturer cases represent an emerging political climate in U.S. banking. . . .
B of A justified freezing the deposits of 10-year customer American Spirit Arms for three weeks beginning Dec. 18 by saying that the deposits were held for “further review.” Even though American Spirit Arms is a properly licensed firearms manufacturer which submits to regular audits by the Bureau of Alcohol, Tobacco, Firearms and Explosives and the Department of Homeland Security, Bank of America also said, “We believe you should not be selling guns and parts on the Internet.” Happily, the Internet played a role in resolving the issue, as business owner Joseph Sirochman told anchorperson Megyn Kelly on Fox News’ America Live.
Another disturbing episode involved McMillan Firearms Manufacturing in April 2012. In expanding a routine “account analysis” meeting to include the larger political issue of overall business purpose, Bank of America directly suggested that the firearms manufacturer take its business elsewhere. Bank of America replied to the allegations here and McMillan responded again here.