Nearly 60 percent of large and midsized U.S. businesses obtained terrorism insurance for their property during 2005--up 10 points from the year before and dramatically higher than 2003's 27 percent, a study by Marsh revealed. Meanwhile, the cost of property terrorism insurance in 2005 was 25 percent lower on average than the year before.

The study found that the purchase of property terrorism insurance in 2005 varied considerably, depending on a company's total insured values, location and industry sector. However, while smaller companies (those with total insured values of less than $100 million) were far less likely in the past to buy this coverage, the study noted nearly half of them did so in 2005.

Take-up rates--the percentage of firms buying the cover--varied considerably by region. About 67 percent of Northeast firms (up from 53 percent) and 58 percent of Midwest companies bought property terrorism insurance last year, compared with 53 percent in the West and 50 percent in the South.