Germany's biggest bank Deutsche Bank AG reported on Monday it estimates a loss of 4.8 billion euro or $6.4 billion on the fourth quarter on what it called exceptional market conditions which impacted sales and trading businesses.

The bank said this loss will ultimately lead to a full year loss of 3.9 billion euro in 2008.

We are very disappointed at this fourth quarter result, said CEO Dr. Josef Ackermann. The exceptionally difficult market environment of the quarter exposed some weaknesses in our platform, and we have determined a number of measures to address these weaknesses. Implementation of these measures is already underway, he added on a statement.

Deutsche Bank's fourth-quarter and full-year 2008 results will be published as scheduled Feb. 5.