As a consequence, the RAND study's authors warn there may be less insurance available for victims of future catastrophic terrorist attacks on U.S. soil. TRIA requires insurers to make terrorism coverage available to commercial policyholders, while establishing reinsurance in the form of a federal guarantee for a portion of the losses.

The RAND researchers observe in the report that TRIA's pending expiration presents an opportune time to evaluate what role the U.S. government should play in the terrorism insurance market, because without an extension or substitute program, insurers will not be in the market for catastrophic terrorism coverage.

The American Insurance Association said in response that the report makes clear the need for prompt action by Congress to extend TRIA, which will now terminate Dec. 31, 2005.

An effort to renew TRIA for two years, while supported by a bipartisan majority in Congress, stalled in the House as Congress raced to adjourn to campaign in the first week of October. The extension also faces opposition from Sen. Richard Shelby, R-Ala., chairman of the Senate Banking Committee. Sen. Shelby wants to wait until next year, and completion of a Treasury Dept. study of the need for any extension, before acting.

Leigh Ann Pusey, AIA senior vice president, government affairs, said that, "While the RAND study makes compelling points for ultimately finding a long-term solution to the challenges of insuring against catastrophic terror, we want to emphasize the urgency of getting TRIA extended as soon as possible."

Ms. Pusey explained that, "As the study authors note, insurers are now negotiating and underwriting policies that will not expire until after TRIA does. This calendar mismatch is creating dysfunction in the marketplace right now?and the dysfunction will only grow until Congress acts."

Marliss A. Browder, federal affairs director for the National Association of Mutual Insurance Companies, added that the comprehensive analysis showed that "insurers were able to mobilize adjusters and effectively and efficiently process claims after 9/11."

However, Ms. Browder added, "the terrorism threat facing this nation post 9/11 remains real as our country continues under an elevated terrorism alert. The fact remains that the United States Government has made significant progress to strengthen our security, but it cannot guarantee that another terrorist attack will not occur.

"If the government cannot give us that assurance, we cannot predict frequency and it is unrealistic to expect the nation's commercial insurers to undertake this risk?and face potential financial ruin," Ms. Browder added, noting that "TRIA has, for the most part, enabled terrorism coverage to be available at reasonable prices and the take-up rates have improved since its enactment."

She said that NAMIC "strongly supports" an extension to TRIA beyond 2005 and this is one of the trade group's top priorities for the post-election ?lame duck' session, scheduled to begin mid-November.

"In the meantime," Ms. Browder added, "we will continue to press our case in Congress as well as energize NAMIC's grassroots base. So many critical economic decisions depend on the availability of terrorism coverage, making the TRIA extension imperative to avoid marketplace instability."

The report, prepared specifically by the Rand Institute for Social Justice, found that civilians killed or injured have received an average of $3.1 million per person from the government, charities and insurance companies, or $8.7 billion.

Emergency personnel killed or injured were given a total of about $1.9 billion. First responders received an average of $1.1 million more than civilians with similar economic losses, the study found. Most of the extra money came from charities.

The majority of the money went to New York City businesses, which received $23.3 billion, according to Rand. Three out of every four dollars that went to businesses came from insurance companies.

In such a large-scale disaster, even the secondary assistance added up to billions of dollars in compensation, the report said. About $3.5 billion was paid to displaced residents, workers who lost their jobs, and those who suffered emotional problems or were exposed to environmental dangers.

The AIA comments were a reaction to statements by study coauthor Lloyd Dixon, that the results raise questions about the future role of insurance companies in the response to any attack.

"It points out the hole that would be created if we don't have terrorism insurance," Mr. Dixon said. "What if the insurers weren't there the next time?"