Swiss Reinsurance Co. estimates its claims resulting from the eartquake in Japan will reach $1.2 billion net.
Swiss Re said Monday that the scale of destruction means it will take longer than usual to assess the damage caused to residential and commercial property.
Spokesman Rolf Tanner noted that damage to nuclear facilities and as a result of radiation contamination isn't covered by insurance policies.
Workers at the damaged Fukushima nuclear plant are struggling to contain radiation after the cooling system was knocked out by the tsunami that followed the quake.
Zurich-based Swiss Re says it has donated $500,000 to the relief and reconstruction effort in Japan.