The announcement that Walter Kielholz is stepping down at Swiss Re comes just three days before his new employer, Credit Suisse, reports its third-quarter figures.
Kielholz, aged 51, will take over as chairman from former Swiss Re CEO Lukas Mühlemann, who announced his resignation from CS in September.
Credit Suisse is forecast to show a net loss of close to SFr2 billion ($1.39 billion), up from a SFr579 million loss in the second quarter.
According to the "NZZ am Sonntag" newspaper, Credit Suisse has told some analysts that the results will include a SFr350 million tax charge.
However, a bank spokesman declined to comment on the report.
The newspaper added that Swiss financial regulators require that all analysts and shareholders receive any important news at the same time.
The CS Group has been hit by huge write-downs at its struggling Winterthur insurance company and has stepped in twice this year with cash injections of SFr3.7 billion to shore up flagging capital.