The companies that provide Americans with their homeowners' and auto insurance made a record $44.8 billion profit last year even after accounting for the claims of policyholders wiped out by Hurricane Katrina and the other big storms of 2005, according to the companies' filings with state regulators.

Top executives described the profit -- an 18.7 percent increase over the previous year -- as a fluke, product of gains in other lines of insurance besides homeowners and a very good year for their investments.

They said that even with the increase, insurers face deep problems that could only be fixed by substantial premium hikes, a scaling back of commitments by several companies to the most disaster-prone areas and, according to some, a greatly expanded role for the state and federal governments in insuring individuals against the largest of catastrophes.

"Unless insurers can get relief, you're going to see a pullback by the private industry," warned Robert P. Hartwig, chief economist of the industry-funded Insurance Information Institute.

In fact, the property casualty insurance industry, which provides homeowners' and auto coverage, made a considerable sum despite paying tens of billions to policyholders as a result of Katrina, widely described as the largest insured disaster in U.S. history, and a string of other storms.

And the industry raised its surplus by more than 7 percent to nearly $427 billion, according to an analysis of company filings by the National Association of Insurance Commissioners. The surplus is intended to provide a cushion in times of high claims.

The industry covered virtually all of its claims and expenses with premiums earned during the year rather than with surplus funds, according to the organization's analysis.

The question is: How, in a year that produced an estimated $56.8 billion in disaster losses, is this possible?

The answer partly is that U.S. insurers purchased disaster insurance of their own before the 2005 storms, much of it from overseas companies.

And so much of the 2005 storm damage was caused by flooding, which Washington handles through the national flood insurance program.

But the industry's performance also reflects a dozen-year effort by insurers to insulate themselves from extreme financial consequences of catastrophe by, among other things, shifting risks borne by companies to policyholders and the public.

The effort started after the last big batch of natural disasters in the early 1990s, among them Hurricane Andrew in Florida in 1992.

The effort has included industry adoption of sophisticated techniques for analyzing catastrophic risk, as well as self-imposed limits on how much companies will cover and where. It also has included successful campaigns to get states or state-created entities to shoulder such dangers as earthquakes in California. And it has involved tightening policy language by, for example, narrowing the definition of "replacement cost" for homes .

Historically, insurers covered a little more than 60 percent of losses in disasters, according to Mr. Hartwig. During the 2004 hurricanes in Florida, they covered less than 50 percent; during Katrina, he said they covered about 30 percent.

The insurance industry has been part of a trend that has picked up steam as the U.S. economy has grown more competitive in recent decades -- a shift of financial risks from business and often government to individual households.

Major insurers, most prominently Allstate, have announced a new round of risk-limiting steps, including approving no new homeowners' policies along stretches of the nation's East and Gulf coasts. Several have called for creation of state and federal funds to serve as financial backstops for the industry in the biggest disasters.

The new proposals have drawn fire.

George K. Bernstein, appointed by President Nixon as the first administrator to oversee the government's flood, riot and crime insurance programs, said private insurers had already pulled out of other risky lines of business. "There's not going to be much left that they do insure by the time it's all over," he warned.

California Insurance Commissioner John Garamendi said: "The insurance industry is running away from risk and leaving policyholders holding the bag."

Among those policyholders are Robert and Denise Sebastian, whose New Orleans house flooded after the walls of one of the city's major canals gave way during Katrina.

Mr. Sebastian, 52, an official with the federal Minerals Management Service, has been trying to collect more than $450,000 he believes his family is owed by St. Paul Travelers and Encompass Insurance, an Allstate subsidiary.

He has managed to get about half of that amount, but only after repeated clashes with the companies and returning several small checks proffered as full payment. "My wife and I are both lawyers," said Mr. Sebastian. "We've put every bit of our wherewithal into pursing these claims, and we're still not settled after seven months. I wonder what happens to the grandmother in Gentilly?"

To be sure, Katrina and last year's other big storms dealt body blows to some insurance companies. Mississippi's No. 2 insurer, Mississippi Farm Bureau Mutual Insurance, went broke after paying $450 million in claims, and is being dissolved, according to state officials. In addition, the final chapter has not been written for several insurers, including State Farm Fire and Casualty Co., USAA and Nationwide Mutual Insurance Co., because of lawsuits filed on behalf of Mississippi policyholders.

Among insurers, the consensus is that the industry is in the best shape it has been in years. Some argue against tampering with success.

"We've been through some of the worst natural disasters and made-made catastrophes in our history, and had some of the best earnings in the last 20 or 30 years," said Frank W. Nutter, president of the Reinsurance Association of America, a Washington trade group.