The news sent share prices in the bank up by five per cent but the write down will force the investment bank to announce a loss.
Equal to about nine per cent of the bank's market value to the end of August, the write down follows just a few months after it bailed out of two hedge funds that faced the full turmoil of the crisis.
Sam Molinaro, chief financial officer, was optimistic that the bank's business was improving.
"I wouldn't want to predict that things couldn't get worse, because they seem to keep surprising people," he told City AM.
He also said that Bear had marked down assets to levels that were conservative.
Morgan Stanley posted bigger write downs than Bear Stearns when it announced $3.7 billion of write downs last week but Bear Stearns has reduced its exposure to sub-prime mortgage bonds since August.
Mr Molinaro described the period as "incredibly challenging".