The XL Group has estimated the preliminary loss estimates related to the storms, pretax and net of reinsurance and reinstatement premiums, range from approximately $50m to $75m, with the majority attributable to XL's reinsurance segment.

The insurer said the preliminary net loss estimates related to the severe weather occurrences, including devastating tornado activity, which affected the Midwest and Southeast US over the periods April 22 – 28 and May 20 – 23, 2011.

According to the XL Group, the company’s estimates are based on its review of individual treaties and policies expected to be impacted along with available client data.