In its annual report the firm, which is Germany's largest bank, stated that continuing difficult market conditions may "require us to write down the carrying values of some of our portfolios of assets, including leveraged loans and loan commitments".
Following the release of the report, Deutsche Bank's shares fell 2.3 per cent to 71.80 euros in Frankfurt.
Last month, Deutsche Bank reported a 48 per cent decline in fourth-quarter profits, but was free of any sub-prime write-downs.
Last year, the bank reported that write-downs related to the sub-prime crisis totalled 2.2 billion euros in the third quarter.
Deutsche Bank has escaped with relatively minimal damage from the mortgage catastrophe compared with its competitors, including Zurich-based UBS AG, which wrote down $14 billion in the second half of 2007.
Banks across the world have written off more than $150 billion since the US sub-prime mortgage crisis began to unfold last summer.