The Zurich-based company estimated its own pre-tax claims burdens from three hurricanes and two quakes at some $3.6 billion (3.05 billion euros) in the third quarter. The world's second largest reinsurer behind Munich Re based on assumed premiums cautioned that the estimates "are subject to a higher than usual degree of uncertainty and may need to be subsequently adjusted as the claims assessment process continues." "The most recent natural catastrophes have been extremely powerful," CEO Christian Mumenthaler said in a statement.