Josef Ackermann, chief executive of Deutsche Bank, has flatly denied the German bank is in merger talks - the third time in five weeks he has been forced to make a public statement to silence merger speculation.

Ackermann is attempting to push through a merger with Credit Suisse Group, according to Wirtschaft Woche, the German magazine, which cited a source on Deutsche's supervisory board. It comes two weeks after Ackermann opened the door to future merger talks at the bank's annual general meeting, but denied it had initiated merger discussions.