Munich Re has conceded its full-year profit target of €2 billion ($2.86 billion) is “increasingly ambitious” due to an unusually high frequency of natural catastrophes.

Announcing a first-quarter interim profit of €485 million ($693 million), up from €437 million ($625 million) in the corresponding quarter last year, the company said storm claims have “left their mark” as the company aims to match or better its 2009 consolidated profit of €2.56 billion ($3.66 billion).

Investment returns help staunch losses in reinsurance, although a quarter of its €2.46 billion ($3.51 billion) return came from one-off disposal gains.

“We will not be able to maintain this level and with it the high returns in the next few quarters,” CFO Jorg Schneider says.

Gross written premium rose an impressive 12.4% to €11.7 billion ($16.7 billion) while Munich Re’s operating result is €770 million ($1.1 billion), compared to €736 million ($1.05 billion) in the first quarter of last year.

The company has also announced a €1 billion ($1.43 billion) share buyback program, adding to the €5 billion ($8.3 billion) it has purchased from shareholders since November 2006.