"As the financial disaster ripples outward, the insurance industry will be in for a very rough time. For instance, Westfield America Inc. signed a 99-year, $3.2 billion lease on the now nonexistent World Trade Center Building only last month. This is merely one example of the size of the insurance claims that will be filed in coming weeks. Staggering claims could be filed by the companies that were tenants of the World Trade Center. Meanwhile, liability insurance for canceled airline flights will be paid out, and life insurance policies for the uncounted dead also must be paid."
this is from stratfor. the whole thing, if you're really interested, is at http://www.stratfor.com/home/0109111940.htm. much of it is pretty obvious, though.