Josef Ackermann, chief executive of Deutsche Bank, has been cleared of charges that he authorised improper payments to former executives of Mannesmann, the German telecoms company, four years ago.

Ackermann was found not guilty of breaking fiduciary duty through his involvement in the paying of €75m ($92m) in bonuses to Mannesmann executives to push through the engineering and telecoms group's 2000 takeover by Vodafone, the UK mobile company.