Zurich Insurance Group said on Monday that two independent probes had concluded there was no "undue pressure" on its financial chief, whose August suicide rocked the Swiss business world.

Switzerland's regulator, the Finma, launched two parallel investigations in the wake of the death of Pierre Wauthier, who had served as the group's chief financial officer since 2011.

One probe sought to establish whether any excessive pressure had driven Wauthier to take his own life, while the other focussed on whether there had been any irregularities in the group's financial reporting.

"The investigations found no indication that Pierre Wauthier was subjected to any undue or inappropriate pressure, and furthermore, the presentation of the financial figures was confirmed as appropriate," Zurich said in a statement Monday.

Wauthier, a 53-year-old French and British citizen who joined Zurich in 1996, was found head at his home on August 26.

The group's Swiss chairman Josef Ackermann a former head of Deutsche Bank, resigned three days later.

Ackermann, 66, said he had decided to quit because he had reasons to believe that Wauthier's family felt he should take a share of the responsibility, though he underlined that any allegations were unfounded.

Ackermann, who had become Zurich's chairman in March 2012, has long been known for his hardball management style and had been criticized by Swiss media as a result.

There was widespread speculation after Wauthier's suicide that he had fallen out with Ackermann over the group's accounts, hence the Finma probe of Zurich's books.

"We are still deeply saddened by the loss of Pierre Wauthier and we are unable to explain the motivation behind his tragic decision," Zurich's new chairman, Dutchman Tom de Swaan, said in a statement Monday.

De Swaan added that Zurich had given its "full support and cooperation" to the probe.