Catastrophe modelers' estimate of insured losses from the storm which struck the Gulf Coast of Louisiana and moved inland last week ranged from a low of $2 billion to as much as $10 million.

Risk Management Solutions today revised its initial insurance loss estimate downward to range from $2.5 billion to $4.5 billion based on new analysis.

According to the Insurance Information Institute, Louisiana's residual market insurer, Citizens Property Insurance Corp., has received 5,000 claims. The I.I.I. also said that taking the average loss estimate of $5.3 billion, Gustav could historically become the eighth most costly hurricane for the insurance industry.

The storm reached Category 3 status on the Saffir-Simpson scale with sustained winds of 115 mph before dropping to a Category 2 storm at landfall.

Oil and gas production fields in the Gulf of Mexico were not seriously impaired, according to reports. According to the federal Minerals Management Service, 90.5 percent of oil and 79.8 percent of natural gas production remain off line (shut-in) while crews re-man rigs and platforms that were evacuated as Gustav approached.

However, the arrival of Hurricane Ike could impact the region, with the National Hurricane Center forecasting the storm could make a turn around the southern portion of the state over the Keys by Wednesday. Maximum sustained winds are forecast to be around 115 mph.

A spokesman for Florida's residual market insurer, Citizens Property Insurance Corp., said the insurer is watching Gustav closely, but models indicate that it is tracking further south than initially feared, away from more populated areas.

Citizens is the number one homeowner insurer in the state with 1.2 million policies in force and a total of more than $2 billion in direct written premium–$1.2 billion of that figure is in high risk area, the spokesman said.

Ike remains a worrisome storm, said Steve E. Smith, president of Property Solutions, Carvill ReAdvisory out of Chicago. He said the long-range forecast remains “troubling” and warned that despite significant error in the long-range forecast it remains “a very serious threat to southern Florida.”

According to Highline Data, a division of Summit Business Media Co., which also owns National Underwriter, the three insurers most heavily impacted by Hanna hitting North Carolina and South Carolina would be State Farm, Allstate and Nationwide.

Between the two states, the three insurers share a total of $3.9 billion in direct written premium exposure from federal flood loss, homeowners and private passenger auto exposure.

(This story was updated at 4:24 p.m.)