Partially state-owned Commerzbank posted a quarterly net loss of €1.86 billion and an annual loss of €4.54 billion.
The quarterly loss, which the bank said was the result of its devaluation of risky assets, was much larger than an average analyst forecast loss of €1.17 billion compiled by Dow Jones Newswires.
"This is not satisfying, but is attributable to two key factors," the statement quoted bank chairman Martin Blessing as saying. "The result reflects the effects of the ongoing economic and financial market crisis - and the crisis is not yet over, although the start of 2010 has been promising with respect to our operating performance."
The full-year result included the nearly-completed financial integration of Dresdner Bank, which forced Commerzbank to book €1.9 billion in costs.
On Monday, the bank had published its fourth quarter operating result, which showed a loss of €1.6 billion that was also attributed to asset writedowns.
For all of 2009, the operating loss climbed to €2.3 billion.
The bank said it expected to post an operating profit this year but warned that on the net level, the bank "will only be in the black if the development of the economy and the financial markets will be very positive."
This year would see "a considerable improvement in customer-focused business," Blessing added.
Commerzbank carried out a recapitalisation last year with German government aid in the amount of €18.2 billion that left the state with a stake of 25 percent in the bank.
It said Tuesday however that "the total impact of the financial market crisis was better than expectations at the beginning of the past year."