Deutsche Bank has publicly denied any disagreement over future strategy between Josef Ackermann, its Swiss chief executive, and senior management - in particular board member Ulrich Cartellieri - amid speculation of a row over the mooted takeover of Postbank, Germany's largest retail bank.

Cartellieri and other members of the supervisory board backed a takeover of Postbank, in a move rejected by Ackermann in favour of a transatlantic merger, according to banking sources in Germany.