One way to lift that burden from companies would be to return to the pre-1983 policy of making Medicare the primary payer of health care costs for people over 65, whether they are working or not.

MEDICAID - By default, Medicaid has become the primary payer for long-term care.

And the approach would probably be most feasible in countries, like Britain, where the government is the primary payer.

The federal government, in the form of Medicare, will be the primary payer of an ACO.

Medicaid a Big Payer Medicaid, the Federal-state insurance program for the poor, was the primary payer for both groups, paying for more than 45 percent of each group.

In some instances Tricare for Life is primary payer when the services are normally a Tricare benefit but not covered by Medicare.

(Medicaid is the primary payer for 68 percent of nursing home residents.)

"If a Blue Cross/ Blue Shield plan is identified as a primary payer, we pay it," she said.

Then it becomes hard to untangle who the primary payer is.

Issue of Liability "The issue is who has liability for those claims in which private insurers are identified as the primary payers," Mr. Difazio said.