1. Insurer obligated to pay losses first when two or more insurers may be responsible for paying the claim. 2. Medicare is a primary payer with respect to Medicaid; for a person eligible under both programs, Medicaid pays only for benefits not covered under Medicare or after Medicare benefits are exhausted. 3. An employer’s health plan if a Medicare patient is covered by that plan, and then Medicare is the secondary payer. 4. Insurance carrier or managed care plan that has the first responsibility under the coordination of benefits clause between two or more insurers.