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An HR Glossary for HR Terms

Glossary of Human Resources Management and Employee Benefit Terms

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Secondary Insurance

What Is Secondary Insurance?

Secondary insurance is when someone is covered under two health plans; one plan will be designated as the primary health insurance plan and the other will be the secondary insurance. The primary insurance is where health claims are submitted first. The secondary insurance will then pay for whatever remaining costs are eligible for coverage under its health plan. 

When two health insurance providers work together in this way to provide coverage, this is called coordination of benefits. Insurance providers can thereby avoid duplicate payments for claims. This doesn’t mean that you get double the payments or reimbursements; however, it may help cover health care costs if one plan has better coverage for a service than the other plan.

Supplementary insurance, like vision, dental, or accident coverage, is also sometimes referred to as secondary insurance. See our glossary entry on supplementary insurance for more information.

Who Can Have Secondary Insurance?

There aren’t eligibility requirements for who can have secondary insurance, but there are three cases when this is most common:

  • Underage children where both parents have health insurance: Both parents can enroll their children on their health insurance plans. Generally, the plan belonging to the parent whose birthday comes first in a calendar year is designated as the primary insurance plan, and the plan belonging to the parent with a later birthday becomes the secondary insurance plan. This is also referred to as the birthday rule (though it’s not a law, more of a best practice among insurers).

  • Adults under age 26 who have health insurance: Under the Affordable Care Act (ACA), unmarried and married children can remain on their parents insurance until age 26. These individuals can also be covered through a school or employer health insurance plan. Their workplace or school plan will be their primary insurance and their parents’ plan will be the secondary insurance.

  • Married adults or domestic partners who both have health insurance: If both individuals in a marriage or domestic partnership have health insurance, they can add their spouse or partner to their plan as a dependent and then that spouse or partner will have both a primary insurance (their own) and a secondary insurance (their spouse or partner’s plan).

Can You Choose Which Plan Is Primary and Which Is Secondary?

The short answer is no, you can’t. As outlined above, an individual’s employer-sponsored plan will always be primary. Even if a spouse or parent’s plan has better coverage or maybe a lower deductible, you can’t submit claims to them first. 

In the case of a minor child, if both parents have the same birthday or are divorced, individuals covered by the plans still won’t be the ones to choose.

  • If both parents have the same birthday, then the plan that has covered a parent the longest will be primary.

  • If parents are divorced or separated, then the birthday rule still applies unless superseded by a judge or divorce decree. Otherwise, the plan of the parent who has custody of the child will be designated as primary.