(Reuters) - At least five U.S. banks, including Bank of America Corp (BAC.N), Citigroup Inc (C.N) and Wells Fargo (WFC.N), will be "materially" impacted by the new accounting rules, Fox-Pitt Kelton said.

The other banks, under the brokerage's coverage, that will be hurt by the new rules are J.P. Morgan Chase & Co (JPM.N) and Fifth Third Bancorp (FITB.O).

The brokerage, which has an "outperform" rating on Bank of America and Wells Fargo, and "in line" ratings on the other three, said that credit cards would have the most meaningful profit-and-loss impact.

The Financial Accounting Standards Board (FASB), which sets U.S. accounting rules, voted on Monday to adopt two rules that could force financial institutions to bring more off balance sheet assets onto their books.

"Consolidation of off-balance sheet assets would obviously increase GAAP and risk-weighted assets. This, along with reduction in tangible capital equity (TCE) and Tier 1 capital... would reduce TCE and Tier 1 ratios," the brokerage said.

Under new rules, a majority of the credit card securitizations and commercial paper conduits are likely to be consolidated, while majority of the mortgage securitizations are unlikely to be consolidated, said Fox-Pitt.

The rules will take effect at the beginning of 2010 and the FASB expects to issue final versions next month.

The changes have been watched closely by investors amid concerns it could force financial firms to book trillions of dollars worth of troubled assets and raise more capital to offset risks.

(Reporting by Archana Shankar in Bangalore; Editing by Himani Sarkar)