It is possible for person to be covered by both Medicare and group health insurance. For example:
- The person is age 65 or over; therefore, he or she is entitled to “premium-free” Medicare Part A.
- The person continues to work beyond age 65; therefore, he or she is still covered by group health insurance through work.
If a person is covered by both Medicare and group health insurance, which insurance pays first is determined by the number of employees employed by the person’s employer:
- If the person works for an employer that has 20 or more employees, the group health plan pays first, and Medicare pays second.
- If the person works for an employer that has less than 20 employees, Medicare pays first, and the group health plan pays second.
If a person has group health coverage through an employer or union (because the person or the person’s spouse is still working) he or she may want to wait to enroll in Part B for these reasons:
- Group health insurance benefits through employers often provide coverage similar to Part B;
- The person would be paying for Part B before it is needed; and
- Medigap open enrollment period might expire before a Medigap policy would be useful.
When the group health coverage eventually ends, the person can enroll in Part B without a late enrollment penalty. The person’s Medigap open enrollment period will then start, allowing the person to sign up for a Medicare Supplement policy.