The report also found that for every $1,000 in revenue, U.S. businesses spend an average of $2.32 on insurance and other measures to manage their primary casualty risk, which are workers' comp, auto and general liability risks.

The conclusions are based on data from 1,433 businesses and government entities compiled through November 2003, the broker said.

Breaking the costs down, workers' comp averaged $1.46 per $1,000 in revenue, while general liability costs were 55 cents and auto liability 31 cents, said Marsh.

The study found that for the past two years, post Sept. 11, as the cost of insurance has increased more businesses are retaining additional risk with higher deductions.

The cost of primary casualty risk rose by close to 7 percent, but retentions rose almost 18 percent in workers' comp, 14 percent in general liability and less than 13 percent in auto liability.

Timothy Brady, a managing director in the U.S. Casualty Practice of Marsh, said businesses elected to keep higher retentions to mitigate higher premium costs.

Larger employers generally enjoy the economy of scale when it comes to controlling their cost of risk, Marsh went on to say. The cost of risk is 16 times larger for smaller businesses than larger, the report found. Businesses with more than $10 billion in revenue pay $1.38 per $1,000 of revenue for their casualty risk programs. On the other hand, businesses with $200 million or less in revenue pay $21.75 per $1,000 in revenue.

Government entities had the highest workers' comp costs, Marsh said, at $8.25 per $1,000 of revenue. Finance, banking and real estate had the lowest at 24 cents per $1,000.

General liability costs were the highest for educational and not-for-profit institutions at $2.38 for every $1,000 of revenue. Financial services again had the lowest costs at 14 cents.

In auto liability, transportation service companies had the highest costs at $1.51 per $1,000 of revenue, which translated to $2,589 per vehicle.

Additional information and copies of the report are available by contacting Peggy Sherertz at 212-345-3393.