Swiss Re's

CEO Jacques Aigrain resigned a week after the Zurich-based reinsurer said it will receive a capital injection of 3 billion Swiss francs ($2.6 billion) from U.S. financier Warren Buffett and warned it expects to lose 1 billion francs ($869 million) for the full year.

Stefan Lippe, the company's deputy CEO and chief operating officer, has been named as Aigrain's successor.

"Having taken measures to reinforce the group's capital strength and further de-risk its investment portfolio, the interests of Swiss Re are now best served by a change in executive leadership," Aigrain said in a statement released by Swiss Re.

Aigrain is taking responsibility for the 62% slide in the company's shares this year, caused in part by losses from its forays beyond traditional insurance, according to an interview the

Wall Street Journal

conducted with the CEO.

Aigrain, a former JPMorgan Chase banker, joined Swiss Re in 2001 and became CEO in 2006.

Moody's last week downgraded its long-term debt rating on Swiss Re and placed the ratings on review for further possible downgrade.