BofA now trades at a mere one-third of its book value, suggesting that investors don’t trust the stated value of its assets relative to its liabilities. A cloud of uncertainty still hangs over its potential losses from duff mortgages inherited through the acquisitions of Countrywide, a big lender, and Merrill Lynch, one-time packager of the most egregious structured securities on Wall Street. A group of investors and New York’s attorney-general have challenged a $8.5 billion settlement the bank struck in June with buyers of mortgage-backed securities that had soured. AIG joined the fun on Monday, suing BofA for $10 billion for mortgage fraud, which the bank denies. The bank admitted recently it will have to pay more than previously expected to compensate Fannie Mae and Freddie Mac for dodgy loans that Countrywide had palmed off onto the housing-finance agencies.