Chubb, the nation's 14-largest property and casualty insurer, fell 2 5/8, to 55 7/16.
A third and perhaps most compelling reason is that casualty insurers are poorly geared to bear the earthquake risks already on their books.
Chubb ranks 12th among the nation's property and casualty insurers, but 68th in the life insurance field.
Nationwide, property and casualty insurers posted record profits last year.
Eight other casualty insurers have recently joined forces in various configurations as the industry deals with deregulation, low interest rates and falling stock prices.
The company, the nation's fourth-largest property and casualty insurer, sold 35 million shares at $25.
And casualty insurers and doctors groups favor legislation to limit medical-malpractice lawsuits.
They are the third largest property and casualty insurer in the United States based on 2010 written premium.
A large personal property and casualty insurer, Allstate should benefit from rising premiums, he said.
Andrew, they said, is unlikely to cause solvency problems for any leading property and casualty insurers.