Most are self-insured companies, so they can only estimate next year's costs, she said, but "the cost line is getting steeper."

A 1974 Federal law prevents states from regulating health plans of self-insured companies.

But states may impose taxes and other assessments on such self-insured companies.

More than half of all employees in the United States now work for such self-insured companies.

Such self-insured companies are exempt from most state insurance regulation.

Under current law, state officials said, they could not even require self-insured companies to report how much they spent on health care.

"More than half the individuals with employment-based coverage are now outside the scope of state regulation" because they work for self-insured companies.

A self-insured company keeps dividends and other returns on the investment of money that it sets aside to pay health claims for employees.

A self-insured company is exempt from state taxes on insurance premiums, which are levied in most states.

A self-insured company can be more flexible than a private insurance company in designing benefits to meet the needs of employees.