If they follow these widely accepted rules, found
here (click me), then the employer plan would be primary if it was their own plan; secondary if it's a parent's plan.
Here is a list of situations and which plan would likely serve as primary insurer and which ones would probably be secondary:
You're married and both you and your spouse have separate health plans | Your employer | Your spouse's employer |
A child has dual coverage by married parents | Whichever parent has the first birthday in calendar year | Parent with later birthday |
A child has divorced parents | Whoever has custody | -- |
A child has own policy (from school or work) and still on parent's policy until 26 | Child's plan | Parent's plan |
A child is married and on spouse's policy and continues on parent's policy until 26 | Child or child's spouse's plan | Parent's plan |
A child under 26 is pregnant and on a parent's plan | Child's plan | -- |
Workers' compensation and health insurance plan | Workers' compensation | Health plan |
COBRA and other insurance | Employer's plan | COBRA |
Medicare and a private health insurance plan | Medicare if employer has 100 or fewer employees; private insurer if more than 100 employees | Private insurer is 100 or fewer employees; Medicare if more than 100 employees |
Veterans Administration (VA) and a private health insurance plan | Private insurer | -- |
Military coverage (TRICARE) and other health insurance | Other insurer | TRICARE except if other plan is Medicaid |
Medicaid and a health insurance plan | Health insurance plan | Medicaid |
Here's more information about the above scenarios:
A child has dual coverage by married parents - In this case, the so-called "birthday rule" will apply. The birthday rule means whichever parent has the first birthday in a calendar year is the one whose insurance plan is considered primary.
Remember -- it's not who is oldest. It's where the birthday (month and day) falls in the calendar year. If parents have the same birthday, the primary coverage will go to the plan that has covered a parent longer.
A child has divorced parents - The child is usually covered by the parent who has custody. If the child’s custodial parent remarried, the step-parent’s plan may provide secondary coverage for the child. The plan of the parent who doesn't have custody usually pays last. If it's joint custody, the birthday rule usually applies.
Note: A divorce decree may also influence which plan is primary. If the divorce states that one parent is financially responsible for the child's healthcare expenses, that parent’s plan should be primary for the child and the other parent’s policy is secondary.
If the decree states that both parents are responsible, their plans would be given the same priority, thus reverting back to the birthday rule for who would pay first.
A child under 26 is pregnant and on a parent's plan - The health insurance status would stay the same for the under 26 child; the parent's insurance serves as secondary.
However, the newborn is different. Once the child is born, he/she will need to be covered by his/her parent - not his/her grandparent. The grandchild is not a dependent to the grandparents. Thus, their insurance would not extend to that child.
Medicaid and a health insurance plan - Medicaid is always the payer of last resort when there are multiple plans.
Veterans Administration (VA) and a private health insurance plan - VA is not considered a health insurance plan. Instead, the VA bills public or private health insurance providers for care, services, prescriptions and supplies. So, if your spouse has a health insurance plan, it would be your health plan.
Military coverage (TRICARE) and other health insurance - TRICARE is considered secondary to all other health plans except Medicaid, TRICARE supplements, state crime compensation programs and other specified federal government programs. Note: If you are on active duty, you can’t use any other health insurance. TRICARE is your only health insurance coverage.
You can locate COB information in the health insurer's certificate of coverage or call your insurance company. The certificate is often online, so you can check your insurance company's site first to see if that is provided there.