"Commerzbank needs to undergo a fundamental transformation," Manfred Knof wrote in the memo, which was seen by Reuters.

The bank has been struggling to generate profits and has announced it is reviewing its strategy, after the arrival of Knof, who joined from Deutsche Bank.

The German lender late last month said it would book 610 million euros ($744.99 million) in restructuring charges in the fourth quarter after reaching an agreement with staff on previously announced headcount reductions.

(Reporting by Edward Taylor and Patricia Uhlig; editing by Tom Sims)