ZURICH (Reuters) - Zurich Insurance <ZURN.VX> said its chairman, ex-Deutsche Bank AG <DBKGn.DE> head Josef Ackermann, will step down immediately, following what appeared to be the suicide of the insurer's financial chief earlier this week.

"I have reasons to believe that the family is of the opinion that I should take my share of responsibility, as unfounded as any allegations might be," Ackermann said in a statement on Thursday.

"As a consequence, I see the possibility of a continued successful board leadership to the benefit of Zurich called into question."

Swiss police have said the death of Zurich's finance chief Pierre Wauthier on Monday appeared to be a suicide. Wauthier is the second top executive in Switzerland to take his own life in five weeks.

(Reporting By Katharina Bart)