The single largest loss in the history of the insurance industry occurred two years ago this month when Hurricane Katrina struck the Gulf Coast, causing $40.6 billion in insured damage. Nearly two years later, the overwhelming majority of claims have been settled. The magnitude of Hurricane Katrina triggered a reexamination of how the United States deals with the financial consequences of natural disasters among insurers, reinsurers and public policymakers, which continues today, according to the Insurance Information Institute (I.I.I.).