Josef Ackermann tried to shake up Zurich Insurance Group AG. Now, allegations that he was partly responsible for the suicide of the chief financial officer are casting a shadow over his 35-year career.

Pierre Wauthier, who was found dead on Aug. 26 at his home near Zug, Switzerland, mentioned Ackermann in a suicide note. The Swiss native, 65, quit as chairman three days later and called the allegations “unfounded.” Zurich Insurance, facing renewed concerns about its financial health, has since said it's looking into whether undue pressure was placed on the CFO.

“No matter which way you cut it, the departure amounts to a personal failure,” said Lutz Roehmeyer, a fund manager at Landesbank Berlin Investment, who helps oversee more than 11 billion euros ($14.5 billion). “He'll be seen either as a bad guy who forced a person to suicide, or someone who couldn't push through what he wanted. This will limit his job opportunities to companies that wouldn't normally have come into question.”