Citigroup (C), Bank of America (BAC) and Wells Fargo (WFC) said in annual reports filed in recent days that they could face $6.7 billion in litigation-related losses in coming years beyond the amounts they have set aside in reserves. None of the banks foresaw any such losses in their filings last year.

The biggest potential hit is at Citi, which says its losses could hit $4 billion as it defends cases that take up five pages in its latest 10-K filing. These range from suits tied to the subprime mortgage mess to the Lehman Brothers bankruptcy to the underwriting of securities backed by U.S. home loans.

Bank of America said in its filing that its losses on legal cases could run $1.5 billion above funds it has reserved for the purpose. Thanks to its acquisition of Countrywide and Merrill Lynch during the financial meltdown, Bank of America has been spending considerable time and money dealing with cases tied to the housing bubble.

Wells Fargo says its losses could run as high as $1.2 billion. The other big banks may size up their legal exposures when they make annual filings in the next  day or two.

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