US financial regulators have ruled the "living wills" of eight of America's largest banks were "not credible" or had "shortcomings", giving the banks until the beginning of October to remedy them or face "more stringent prudential requirements."The Federal Deposit Insurance Corporation and the Federal Reserve Board on Wednesday said they "jointly determined that each of the 2015 resolution plans of Bank of America, Bank of New York Mellon, JP Morgan Chase, State Street, and Wells Fargo was not credible or would not facilitate an orderly resolution" under relevant US laws.The agencies "jointly identified weaknesses in the 2015 resolution plans of Goldman Sachs and Morgan Stanley that the firms must address."The Federal Reserve Board, but not the FDIC, "identified a deficiency in Morgan Stanley's plan and found that the plan was not credible or would not facilitate an orderly resolution."Citigroup's 2015 resolution plan was the most acceptable of the bunch, featuring mere "shortcomings that the firm must address."