The moves mark a dramatic downturn in the career of the 65-year-old former Swiss army colonel, who rose to become one of Europe's most powerful bankers, leading Deutsche for a decade during the global financial crisis and euro zone debt turmoil.

“The suicide of the finance chief of Zurich was a complete surprise to everyone,” said Ackermann, looking calm and composed in a blue suit and tie.

“However I resolutely reject the idea, contained in the note from the deceased, that I was responsible or partly responsible for his suicide. There are no grounds whatsoever for his accusations against me.”

Ackermann did not once mention Wauthier by name, referring to him repeatedly as the “finance chief”. He said he had not spoken with his former colleague's family.

The biography by his personal spokesman Stefan Baron, titled “Late remorse: a close-up of Josef Ackermann,” depicts him as an impatient, exacting boss who demanded excellence from staff but also took colleagues and their partners away for weekend breaks, including a trip to India to play elephant polo.

“It's not a cakewalk to work for Josef Ackermann,” Baron writes. “With deadly precision he uncovers even the smallest weakness in an argument or presentation, and will push for improvements until he feels it is perfect.

“The Swiss is impatient and wants to see results. Nobody should expect a 'thank you' after working through the night.”

AGGRESSIVE TONE

Ackermann said his encounters with Wauthier, who left a wife and two children, had been infrequent and limited to exchanges about the insurer's accounts that he described as “always businesslike and based on mutual respect”.

Sources have told Reuters that at a meeting in mid-August, a day before second quarter earnings were released, Ackermann insisted that Wauthier make changes to the results presentation, leading Zurich to signal a lack of progress on business targets.

Less than two weeks later, Wauthier hanged himself at his home near Zug. In the note he described himself as demoralised due to a new, aggressive tone at Zurich under Ackermann, according to people who have seen the letter.

Asked how he was coping with the suicide, Ackermann replied: “This was a very tragic event, no question. Only I didn't find what then occurred, these accusations, how shall I say it, to be very fair.”

Ackermann returned to his native Switzerland in March of last year to take on the role at Zurich after 10 years leading Deutsche. Explaining why he stepped down so quickly after the suicide, he said Wauthier's family had threatened to go to the media with details of the note.

“There are many who asked me, encouraged me to carry on,” he said. In light of the incident and the threats, however, he came to the conclusion that it would not have been possible to carry out his duties as chairman with the “required resolve”.

He said he would remain on the boards of companies such asRoyal Dutch Shell and Sweden's Investor AB. But people close to him have said he is likely to take a lower profile in public in the coming months.

Ackermann had not been out in public since Wauthier's suicide, except when he was seen at an evening soccer World Cup qualifying match between Switzerland and Iceland on the day Zurich held a memorial service for the chief financial officer.